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LaDue CA, Hunt KE, Kiso WK, Freeman EW. Hormonal variation and temporal dynamics of musth in Asian elephants ( Elephas maximus) are associated with age, body condition and the social environment. Conserv Physiol 2023; 11:coad019. [PMID: 38026805 PMCID: PMC10660383 DOI: 10.1093/conphys/coad019] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 12/01/2023]
Abstract
The sustainability of endangered Asian elephants in human care is threatened in part by low breeding success and concerns over individual animal wellbeing. Male elephants have received less research attention compared to females, yet males deserve special consideration due to their unique reproductive biology (particularly the sexual state of "musth") and the complex interaction of physiological, environmental, and social pressures they face. We measured fecal androgen metabolites (FAMs), fecal glucocorticoid metabolites (FGMs), and fecal triiodothyronine metabolites (FT3s) collected weekly over approximately 12 months from 26 male Asian elephants housed in zoos across the US, hypothesizing that FAM, FGM, and FT3 concentrations would be associated with temporal correlates of musth and would vary further with intrinsic (musth status, age, body condition) and extrinsic (social environment) factors. The duration of each musth episode was positively associated with exposure to male conspecifics and negatively associated with body condition. Further, elevated FAM concentrations were associated with social exposure, age, and body condition, and FGM concentrations also varied with age and body condition. FT3 concentrations were not associated with any factor we measured. We also identified periods of lower FAM concentration than confirmed musth episodes (but still higher than baseline FAM concentrations) that we termed "elevated FAM episodes." The durations of these episodes were negatively correlated with exposure to other male elephants. Together, these results provide evidence that hormone profiles (including those that are predicted to change around musth) vary significantly between male Asian elephants in a way that may be attributed to intrinsic and extrinsic factors. Studies like these serve to enhance the sustainability of ex-situ populations by providing wildlife managers with information to enhance the health, welfare, and reproduction of threatened species like Asian elephants.
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Affiliation(s)
- Chase A LaDue
- Department of Environmental Science and Policy, 4400 University Drive, MSN 5F2, George Mason University, Fairfax, VA 22030, USA
- Oklahoma City Zoo and Botanical Garden, 2000 Remington Place, Oklahoma City, OK 73111, USA
| | - Kathleen E Hunt
- Department of Biology, George Mason University, 10900 University Boulevard, Manassas, VA 20110, USA
- Smithsonian-Mason School of Conservation, 1500 Remount Road, Front Royal, VA 22630, USA
| | - Wendy K Kiso
- White Oak Conservation Foundation, 581705 White Oak Road, Yulee, FL 32097, USA
- Colossal Biosciences, 3309 Elm Street, Dallas, TX 75226, USA
| | - Elizabeth W Freeman
- School of Integrative Studies, 4400 University Drive, MSN 5D3, George Mason University, Fairfax, VA 22030, USA
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Caspar KR, Stopka P, Issel D, Katschak KH, Zöllner T, Zupanc S, Žáček P, Begall S. Perioral secretions enable complex social signaling in African mole-rats (genus Fukomys). Sci Rep 2022; 12:22366. [PMID: 36572727 DOI: 10.1038/s41598-022-26351-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 12/13/2022] [Indexed: 12/28/2022] Open
Abstract
Subterranean common mole-rats of the genus Fukomys (family Bathyergidae) live in large, cooperatively-breeding families. Odor cues have been hypothesized to play an important role in mediating social behaviors in the underground ecotope, but only little is known about the role of olfactory signaling in burrowing mammals. Here we characterize the so far neglected perioral glands of Fukomys and other African mole-rats as an important source of olfactory social information. Histology demonstrates these structures to be derived sebaceous glands that are developed regardless of sex and reproductive status. However, gland activity is higher in Fukomys males, leading to sexually dimorphic patterns of stain and clotting of the facial pelage. Behavioral assays revealed that conspecifics prefer male but not female perioral swabs over scent samples from the back fur and that male sebum causes similar attraction as anogenital scent, a known source of social information in Fukomys. Finally, we assessed volatile compounds in the perioral sebum of the giant mole-rat (Fukomys mechowii) via GCxGC-MS-based metabolomic profiling. Volatiles display pronounced sex-specific signatures but also allow to differentiate between intrasexual reproductive status groups. These different lines of evidence suggest that mole-rat perioral glands provide complex odor signals which play a crucial role in social communication.
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Glaeser SS, Edwards KL, Paris S, Scarlata C, Lee B, Wielebnowski N, Finnell S, Somgird C, Brown JL. Characterization of Longitudinal Testosterone, Cortisol, and Musth in Male Asian Elephants ( Elephas maximus), Effects of Aging, and Adrenal Responses to Social Changes and Health Events. Animals (Basel) 2022; 12:1332. [PMID: 35625178 DOI: 10.3390/ani12101332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/04/2022] [Accepted: 05/19/2022] [Indexed: 01/09/2023] Open
Abstract
Simple Summary The conservation of endangered species and sustainability of managed populations requires good health and welfare of individuals. Male elephants experience a biological phenomenon called “musth”, characterized by a suite of physiological and behavioral changes which serve to facilitate copulation between the sexes, but can also pose unique challenges under human care. This study characterized longitudinal patterns of circulating testosterone and cortisol in relation to musth in four adult Asian elephant bulls and assessed age-related effects on musth activity and adrenal responses to social changes and clinical health events. All bulls exhibited regular annual musth cycles, and there was no clear evidence of chronically elevated cortisol secretion outside of musth. Circulating cortisol covaried positively with testosterone and musth, highlighting intrinsic patterns that should be considered when evaluating the impact of changes on adrenal glucocorticoid activity. Testosterone decreased with age in sexually mature bulls, whereas age-related changes in cortisol varied across individuals, with the three older bulls showing the greatest rate of change during musth. Changes in cortisol were associated with treatment for Mycobacterium tuberculosis in two bulls, but not with activation of disease. In contrast to physiological factors, there was no evidence that social changes involving male herdmates impacted adrenal glucocorticoid activity in the short term. This study highlights the importance of longitudinal hormone monitoring to track changes in physiological function and identify factors that may influence welfare, which is important for making more informed decisions on how to manage male elephants under varying degrees of human care. Abstract The conservation of endangered species and sustainability of managed populations requires considerations to ensure the health and welfare of individuals. Male elephants experience a biological phenomenon called “musth”, which is characterized by increased testosterone production, temporal gland secretion and urine dribbling, heightened aggression and sexual behavior, and therefore can pose unique challenges for human safety and animal welfare. This study characterized longitudinal (9 to 22 years) patterns of circulating testosterone and cortisol in relation to musth in four adult Asian elephant bulls spanning ages from 12 to 54 years. Age-related effects on musth activity and adrenal responses to social changes and clinical health events were also examined. All bulls exhibited regular annual musth cycles. Circulating cortisol covaried positively with testosterone and musth, highlighting intrinsic patterns that should be considered when evaluating the impact of social, health, and environmental changes on adrenal glucocorticoid activity. Except for an end-of-life cortisol increase in one bull, there was no clear evidence of chronically elevated cortisol secretion outside of musth in any individual. Testosterone decreased with age in sexually mature bulls, whereas age-related changes in cortisol varied across individuals, with the three older bulls showing the greatest rate of change during musth versus inter-musth periods. In contrast to physiological factors, there was no evidence of social factors, such as addition of a new male and death of male herdmates, impacting adrenal glucocorticoid activity in these bulls in the short term. Changes in cortisol were associated with treatment for Mycobacterium tuberculosis (M. tb) in two bulls, increasing after start of treatment and decreasing with cessation of treatment, but were not clearly associated with activation of disease. This study highlights the importance of longitudinal hormone monitoring to track changes in physiological function and responses to social, health, and environmental change in elephant bulls, which is important for making more informed decisions on how to manage male elephants under varying degrees of human care to ensure welfare and safety.
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Schulte BA, LaDue CA. The Chemical Ecology of Elephants: 21st Century Additions to Our Understanding and Future Outlooks. Animals (Basel) 2021; 11:2860. [PMID: 34679881 PMCID: PMC8532676 DOI: 10.3390/ani11102860] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/24/2021] [Accepted: 09/28/2021] [Indexed: 01/19/2023] Open
Abstract
Chemical signals are the oldest and most ubiquitous means of mediating intra- and interspecific interactions. The three extant species of elephants, the Asian elephant and the two African species, savanna and forest share sociobiological patterns in which chemical signals play a vital role. Elephants emit secretions and excretions and display behaviors that reveal the importance of odors in their interactions. In this review, we begin with a brief introduction of research in elephant chemical ecology leading up to the 21st century, and then we summarize the body of work that has built upon it and occurred in the last c. 20 years. The 21st century has expanded our understanding on elephant chemical ecology, revealing their use of odors to detect potential threats and make dietary choices. Furthermore, complementary in situ and ex situ studies have allowed the careful observations of captive elephants to be extended to fieldwork involving their wild counterparts. While important advances have been made in the 21st century, further work should investigate the roles of chemical signaling in elephants and how these signals interact with other sensory modalities. All three elephant species are threatened with extinction, and we suggest that chemical ecology can be applied for targeted conservation efforts.
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Affiliation(s)
- Bruce A. Schulte
- Department of Biology, Western Kentucky University, Bowling Green, KY 42101, USA
| | - Chase A. LaDue
- Department of Environmental Science and Policy, George Mason University, Fairfax, VA 22030, USA;
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LaDue CA, Schulte BA, Kiso WK, Freeman EW. Musth and sexual selection in elephants: a review of signalling properties and potential fitness consequences. BEHAVIOUR 2021. [DOI: 10.1163/1568539x-bja10120] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
Sexual selection mediated by multimodal signals is common among polygynous species, including seasonally breeding mammals. Indirect benefit models provide plausible explanations for how and why mate selection can occur in the absence of direct benefits. Musth — an asynchronous reproductive state in male elephants — facilitates both inter- and intrasexual selection via indirect benefits, and it is further communicated through a multimodal signal. In this review, we synthesise existing evidence that supports the hypothesis that musth is a multimodal signal subject to sexual selection and that male elephants increase their direct fitness by propagating this signal while females accrue indirect benefits. Musth is characterised by a suite of physiological and behavioural changes, serving to facilitate copulation between the sexes, and via multisensory modalities musth conveys honest information about the condition of a male. Female elephants mate preferentially with musth males, increasing their own fitness in the absence of direct benefits. In addition, musth resolves dynamic dominance hierarchies among male elephants and often eliminates the need for costly physical combat. Future work in this field should investigate potential postcopulatory selection mechanisms in elephants, including sperm competition and cryptic female choice. These topics join other fundamental questions related to sexual selection, signalling, and indirect benefits that are still unanswered in elephants.
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Affiliation(s)
- Chase A. LaDue
- Department of Environmental Science and Policy, George Mason University, Fairfax, VA, USA
| | - Bruce A. Schulte
- Department of Biology, Western Kentucky University, Bowling Green, KY, USA
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Keenan TF, McLellan WA, Rommel SA, Costidis AM, Harms CA, Thewissen 'HJ, Rotstein DS, Gay MD, Potter CW, Taylor AR, Wang Y, Pabst DA. Gross and histological morphology of the cervical gill slit gland of the pygmy sperm whale (Kogia breviceps). Anat Rec (Hoboken) 2021; 305:688-703. [PMID: 34288509 DOI: 10.1002/ar.24707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/14/2021] [Indexed: 11/11/2022]
Abstract
Odontocete cetaceans have undergone profound modifications to their integument and sensory systems and are generally thought to lack specialized exocrine glands that in terrestrial mammals function to produce chemical signals (Thewissen & Nummela, 2008). Keenan-Bateman et al. (2016, 2018), though, introduced an enigmatic exocrine gland, associated with the false gill slit pigmentation pattern in Kogia breviceps. These authors provided a preliminary description of this cervical gill slit gland in their helminthological studies of the parasitic nematode, Crassicauda magna. This study offers the first detailed gross and histological description of this gland and reports upon key differences between immature and mature individuals. Investigation reveals it is a complex, compound tubuloalveolar gland with a well-defined duct that leads to a large, and expandable central chamber, which in turn leads to two caudally projecting diverticula. All regions of the gland contain branched tubular and alveolar secretory regions, although most are found in the caudal diverticula, where the secretory process is holocrine. The gland lies between slips of cutaneous muscle, and is innervated by lamellar corpuscles, resembling Pacinian's corpuscles, suggesting that its secretory product may be actively expressed into the environment. Mature K. breviceps display larger gland size, and increased functional activity in glandular tissues, as compared to immature individuals. These results demonstrate that the cervical gill slit gland of K. breviceps shares morphological features of the specialized, chemical signaling, exocrine glands of terrestrial members of the Cetartiodactyla.
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Affiliation(s)
- Tiffany F Keenan
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina
| | - William A McLellan
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina
| | - Sentiel A Rommel
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina
| | | | - Craig A Harms
- Center for Marine Sciences and Technology, North Carolina State University, Morehead City, North Carolina
| | - 'Hans' Jgm Thewissen
- Department of Anatomy/Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio
| | | | - Mark D Gay
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina
| | - Charles W Potter
- Department of Vertebrate Zoology, Smithsonian Institution, National Museum of Natural History, Washington, District of Columbia, USA
| | - Alison R Taylor
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina
| | - Ying Wang
- University of North Carolina Wilmington, Department of Chemistry and Biochemistry, Wilmington, North Carolina
| | - D Ann Pabst
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina
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Caspers J, Radespiel U, Zimmermann E, Schulz S. Volatile Urinary Signals of Two Nocturnal Primates, Microcebus murinus and M. lehilahytsara. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00158] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Faulkes CG, Elmore JS, Baines DA, Fenton B, Simmons NB, Clare EL. Chemical characterisation of potential pheromones from the shoulder gland of the Northern yellow-shouldered-bat, Sturnira parvidens (Phyllostomidae: Stenodermatinae). PeerJ 2019; 7:e7734. [PMID: 31579609 PMCID: PMC6754726 DOI: 10.7717/peerj.7734] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 08/23/2019] [Indexed: 11/22/2022] Open
Abstract
Bats of the genus Sturnira (Family Phyllostomidae) are characterised by shoulder glands that are more developed in reproductively mature adult males. The glands produce a waxy secretion that accumulates on the fur around the gland, dyeing the fur a dark colour and giving off a pungent odour. These shoulder glands are thought to play a role in their reproductive behaviour. Using gas chromatography–mass spectrometry, we analysed solvent extracts of fur surrounding the shoulder gland in the northern-shouldered bat, Sturnira parvidens to (i) characterise the chemical composition of shoulder gland secretions for the first time, and (ii) look for differences in chemical composition among and between adult males, sub-adult/juvenile males and adult females. Fur solvent extracts were analysed as liquids and also further extracted using headspace solid-phase microextraction to identify volatile components in the odour itself. Odour fingerprint analysis using non-metric multidimensional scaling plots and multivariate analysis revealed clear and significant differences (P < 0.001) between adult males vs both juvenile males and adult females. The chemical components of the shoulder gland secretion included terpenes and phenolics, together with alcohols and esters, most likely derived from the frugivorous diet of the bat. Many of the compounds identified were found exclusively or in elevated quantities among adult (reproductive) males compared with adult females and non-reproductive (juvenile) males. This strongly suggests a specific role in male–female attraction although a function in male–male competition and/or species recognition is also possible.
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Affiliation(s)
- Chris G Faulkes
- School of Biological & Chemical Sciences, Queen Mary University of London, London, UK
| | - J Stephen Elmore
- Department of Food and Nutritional Sciences, University of Reading, Reading, UK
| | | | - Brock Fenton
- Department of Biology, University of Western Ontario, London, ON, Canada
| | - Nancy B Simmons
- Department of Mammalogy Division of Vertebrate Zoology, American Museum of Natural History, New York, NY, USA
| | - Elizabeth L Clare
- School of Biological & Chemical Sciences, Queen Mary University of London, London, UK
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Chave E, Edwards KL, Paris S, Prado N, Morfeld KA, Brown JL. Variation in metabolic factors and gonadal, pituitary, thyroid, and adrenal hormones in association with musth in African and Asian elephant bulls. Gen Comp Endocrinol 2019; 276:1-13. [PMID: 30735672 DOI: 10.1016/j.ygcen.2019.02.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 02/03/2019] [Accepted: 02/04/2019] [Indexed: 11/28/2022]
Abstract
Longitudinal analyses of serum testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin, glucose, insulin, triglycerides, cholesterol, total and free thyroxine (T4), total triiodothyronine (T3), thyroid stimulating hormone (TSH), and cortisol were conducted to investigate pituitary, metabolic, and adrenal changes related to testicular function and musth status in zoo-housed elephant bulls. Blood samples were collected twice a month for 12 months from 14 African and 12 Asian bulls at 17 facilities in North America. Building on previous studies, our results show that musth is associated with increased testosterone, LH, FSH, and cortisol secretion, and a decrease in thyroid hormone (total and free T4) production. In addition, glucose and triglycerides were higher during musth than non-musth periods, indicative of altered sugar and fat metabolism. There were significant differences associated with age for LH, FSH and testosterone, all increasing, whereas the glucose-to-insulin ratio (G:I) decreased with age. A species comparison found African and Asian elephants differed in measures of insulin, prolactin, cholesterol and the G:I. Across all hormones, high inter-individual variability was observed, making it difficult to define a general musth endocrine profile or to assess musth status from single samples. These results highlight the need for facilities hosting bulls to closely and consistently monitor each individual from an early age and throughout musth and non-musth periods to determine the pattern for each male.
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Affiliation(s)
- Emmanuelle Chave
- Center for Species Survival, Smithsonian Conservation Biology Institute, 1500 Remount Rd., Front Royal, VA 22630, USA; Université François-Rabelais, 60 Rue du Plat d'Étain, 37000 Tours, France
| | - Katie L Edwards
- Center for Species Survival, Smithsonian Conservation Biology Institute, 1500 Remount Rd., Front Royal, VA 22630, USA.
| | - Steve Paris
- Center for Species Survival, Smithsonian Conservation Biology Institute, 1500 Remount Rd., Front Royal, VA 22630, USA
| | - Natalia Prado
- Center for Species Survival, Smithsonian Conservation Biology Institute, 1500 Remount Rd., Front Royal, VA 22630, USA
| | - Kari A Morfeld
- Lincoln Children's Zoo, 1222 S 27th Street, Lincoln, NE 68502, USA
| | - Janine L Brown
- Center for Species Survival, Smithsonian Conservation Biology Institute, 1500 Remount Rd., Front Royal, VA 22630, USA.
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Jebb D, Hiller M. Recurrent loss of HMGCS2 shows that ketogenesis is not essential for the evolution of large mammalian brains. eLife 2018; 7:38906. [PMID: 30322448 PMCID: PMC6191284 DOI: 10.7554/elife.38906] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 09/09/2018] [Indexed: 12/04/2022] Open
Abstract
Apart from glucose, fatty acid-derived ketone bodies provide metabolic energy for the brain during fasting and neonatal development. We investigated the evolution of HMGCS2, the key enzyme required for ketone body biosynthesis (ketogenesis). Unexpectedly, we found that three mammalian lineages, comprising cetaceans (dolphins and whales), elephants and mastodons, and Old World fruit bats have lost this gene. Remarkably, many of these species have exceptionally large brains and signs of intelligent behavior. While fruit bats are sensitive to starvation, cetaceans and elephants can still withstand periods of fasting. This suggests that alternative strategies to fuel large brains during fasting evolved repeatedly and reveals flexibility in mammalian energy metabolism. Furthermore, we show that HMGCS2 loss preceded brain size expansion in toothed whales and elephants. Thus, while ketogenesis was likely important for brain size expansion in modern humans, ketogenesis is not a universal precondition for the evolution of large mammalian brains. Our brain requires a lot of energy to work properly. Sugars are usually the main type of fuel for the body, but when they run low – for example during a food shortage – fat, in the form of fatty acids, can be used instead. However, the brain cannot directly process these molecules; instead, fatty acids need to go through ketogenesis, a process that turns fat into ketone bodies, which the organ can then burn. Scientists believe that the ability to create ketone bodies was essential for us to evolve large brains. Yet, it is still unclear if all mammals can transform fatty acids into ketone bodies. One way to look into this question is to track whether other species have HMGCS2, the main enzyme that drives ketogenesis. Jebb and Hiller examined the genomes of 70 different species of mammals for the gene that codes for HMGCS2. The comparisons revealed that cetaceans (whales, dolphins and porpoises), Old World fruit bats and the African savanna elephant have all independently lost their working version of HMGCS2. Yet, many members of these three groups have evolved brains that are large for their body size. The genetic analyses showed that dolphins and elephants developed big brains after the enzyme became inactive, challenging the idea that HMGCS2 – and by extension ketogenesis – is always required for the evolution of large brains. These results may also be useful for conservation efforts. Many fruit bats across the world are severely threatened, and their lack of ketogenesis could explain why these animals are highly sensitive to starvation and quickly die when food becomes scarce.
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Affiliation(s)
- David Jebb
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.,Center for Systems Biology Dresden, Dresden, Germany
| | - Michael Hiller
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.,Center for Systems Biology Dresden, Dresden, Germany
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Vijayakrishnan S, Kumar MA, Umapathy G, Kumar V, Sinha A. Physiological stress responses in wild Asian elephants Elephas maximus in a human-dominated landscape in the Western Ghats, southern India. Gen Comp Endocrinol 2018; 266:150-156. [PMID: 29777687 DOI: 10.1016/j.ygcen.2018.05.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/11/2018] [Accepted: 05/07/2018] [Indexed: 01/13/2023]
Abstract
Increasing anthropogenic pressures on forests, especially in the tropical regions of the world, have restricted several large mammalian species such as the Asian elephant to fragmented habitats within human-dominated landscapes. In this study, we assessed the effects of an anthropogenic landscape and its associated conflict with humans on the physiological stress responses displayed by Asian elephants in the Anamalai Hills of the Western Ghats mountains in south India. We have quantified faecal glucocorticoid metabolite (FGM) concentrations in focal individual elephants within and across herds, inhabiting both anthropogenic and natural habitats, and evaluated their physiological responses to different socio-ecological situations between November 2013 and April 2014. Physiological stress responses varied significantly among the tested elephant age- and sex categories but not across different types of social organisation. Adults generally showed higher FGM concentrations, even in the absence of stressors, than did any other age category. Males also appeared to have higher stress responses than did females. Although there was no significant variation in mean stress levels between elephants on the plateau in the absence of human interactions and those in adjacent, relatively undisturbed forest habitats, FGM concentrations increased significantly for adult and subadult individuals as well as for calves following drives, during which elephants were driven off aggressively by people. Our study emphasises the general importance of understanding individual variation in physiology and behaviour within a population of a seriously threatened mammalian species, the Asian elephant, and specifically highlights the need for long-term monitoring of the stress physiology and behavioural responses of individual elephants across both human-dominated and natural landscapes. Such studies would not only provide comprehensive insights into the adaptive biology of elephants in changing ecological regimes but also aid in the development of effective management and conservation strategies for endangered populations of the species.
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Affiliation(s)
- Sreedhar Vijayakrishnan
- Postgraduate Programme in Wildlife Biology and Conservation, Wildlife Conservation Society - India Program and National Centre for Biological Sciences, Bangalore, India; Nature Conservation Foundation, Mysore, India; National Institute of Advanced Studies, Bangalore, India.
| | | | - G Umapathy
- Laboratory for the Conservation of Endangered Species, Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Vinod Kumar
- Laboratory for the Conservation of Endangered Species, Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Anindya Sinha
- Nature Conservation Foundation, Mysore, India; National Institute of Advanced Studies, Bangalore, India; Indian Institute of Science Education and Research, Kolkata, India
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Stritih N, Žunič Kosi A. Olfactory signaling of aggressive intent in male-male contests of cave crickets (Troglophilus neglectus; Orthoptera: Rhaphidophoridae). PLoS One 2017; 12:e0187512. [PMID: 29112984 PMCID: PMC5675388 DOI: 10.1371/journal.pone.0187512] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/22/2017] [Indexed: 11/19/2022] Open
Abstract
In animal contests, communicating aggressive motivation is most often mediated by visual or acoustic signals, while chemical signals are not expected to serve such a function since they are less able to be modulated by the sender during the changing behavioral context. We describe a rare example of ephemeral olfactory signals in terrestrial animals, signals that are emitted via protrusive scent glands in male cave crickets Troglophilus neglectus (Orthoptera, Rhaphidophoridae) to reflect the state of the signaler's aggression. We correlate the intensity of behaviorally expressed aggression of the individuals in dyadic contests with the frequency and extent of their gland tissue protrusion, the latter serving as an indication of the amount of released odor. We detected large amounts of odor release during brief gland protrusions, and the absence of its release during gland retraction. Males protruded the glands during and after encountering a rival, with the degree of protrusion increasing with the intensity of the signalers' aggression. During the encounters, the degree of gland protrusion increased most strongly with the occurrence of the elevated body posture, directly preceding the attack. This degree was significantly higher in encounter winners than in losers displaying such posture, suggesting the highly important role of the released odor for contest resolution. After the encounters, glands were protruded almost exclusively by winners, apparently announcing victory. We tested for the function of the olfactory signals also directly, by preventing gland tissue protrusion in symmetric and asymmetric treatments of the contestants. Treating only the dominant individuals decreased the percentage of encounters they won by over 60%, while treating both contestants elicited a significant increase in the frequency and duration of fights. During contests, the olfactory signals of T. neglectus apparently function as a highly effective threat, which prevents maximal contest escalation and decreases the conflict-related costs.
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Affiliation(s)
- Nataša Stritih
- National Institute of Biology, Department of Organisms and Ecosystems Research, Ljubljana, Slovenia
- * E-mail:
| | - Alenka Žunič Kosi
- National Institute of Biology, Department of Organisms and Ecosystems Research, Ljubljana, Slovenia
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Somgird C, Sripiboon S, Mahasawangkul S, Boonprasert K, Brown JL, Stout TAE, Colenbrander B, Thitaram C. Differential testosterone response to GnRH-induced LH release before and after musth in adult Asian elephant (Elephas maximus) bulls. Theriogenology 2015; 85:1225-32. [PMID: 26774889 DOI: 10.1016/j.theriogenology.2015.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Revised: 12/06/2015] [Accepted: 12/07/2015] [Indexed: 11/30/2022]
Abstract
Bull elephants exhibit marked increases in testosterone secretion during musth, and studies have shown a heightened sensitivity of the testis to GnRH-stimulated testosterone production in musth compared to nonmusth males. However, activity of the hypothalamo-pituitary-gonadal axis before or soon after musth has not been studied in detail. The aim of this study was to evaluate LH and testosterone responses to GnRH challenge in nine adult Asian elephant (Elephas maximus) bulls during three periods relative to musth: premusth, postmusth, and nonmusth. Bulls were administered 80 μg of a GnRH agonist, and blood was collected before and after injection to monitor serum hormone concentrations. The same bulls were injected with saline 2 weeks before each GnRH challenge and monitored using the same blood collection protocol. All bulls responded to GnRH, but not saline, with an increase in LH and testosterone during all three periods. The mean peak LH (1.76 ± 0.19 ng/mL; P < 0.001) and testosterone (6.71 ± 1.62 ng/mL; P = 0.019) concentrations after GnRH were higher than the respective baselines (0.57 ± 0.07 ng/mL, 3.05 ± 0.60 ng/mL). Although basal- and GnRH-induced LH secretion were similar across the stages, evaluation of the area under the curve in GnRH-treated bulls indicated that the testosterone response was greatest during premusth (2.84 ± 0.76 area units; P = 0.019) compared to postmusth (2.02 ± 0.63 area units), and nonmusth (2.01 ± 0.46 area units). This confirms earlier reports that GnRH stimulates LH release and subsequent testosterone production in bull elephants. Furthermore, although the hypothalamo-pituitary-gonadal axis is active throughout the year, the testis appears to be more responsive to LH in terms of testosterone production in the period leading up to musth, compared to the nonmusth and postmusth periods. This heightened sensitivity, perhaps as a result of LH receptor up-regulation, may prime the testis for maximal testosterone production, leading to the physiological and behavioral changes associated with musth.
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Affiliation(s)
- Chaleamchat Somgird
- Department of Companion Animal and Wildlife Clinics, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand; Center of Excellence in Elephant Research and Education, Chiang Mai University, Chiang Mai, Thailand.
| | - Supaphen Sripiboon
- Center of Excellence in Elephant Research and Education, Chiang Mai University, Chiang Mai, Thailand
| | - Sittidet Mahasawangkul
- Thai Elephant Conservation Center, National Elephant Institute, Forest Industry Organization, Lampang, Thailand
| | - Khajohnpat Boonprasert
- Thai Elephant Conservation Center, National Elephant Institute, Forest Industry Organization, Lampang, Thailand
| | - Janine L Brown
- Smithsonian Conservation Biology Institute, Smithsonian Institution, Front Royal, Virginia, USA
| | - Tom A E Stout
- Faculty of Veterinary Medicine, Utrecht University, CM, Utrecht, The Netherlands; Faculty of Veterinary Sciences, University of Pretoria, South Africa
| | - Ben Colenbrander
- Faculty of Veterinary Medicine, Utrecht University, CM, Utrecht, The Netherlands
| | - Chatchote Thitaram
- Department of Companion Animal and Wildlife Clinics, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand; Center of Excellence in Elephant Research and Education, Chiang Mai University, Chiang Mai, Thailand.
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Mochalski P, Al-Zoairy R, Niederwanger A, Unterkofler K, Amann A. Quantitative analysis of volatile organic compounds released and consumed by rat L6 skeletal muscle cells in vitro. J Breath Res 2014; 8:046003. [PMID: 25307263 PMCID: PMC4913865 DOI: 10.1088/1752-7155/8/4/046003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Knowledge of the release of volatile organic compounds (VOCs) by cells provides important information on the origin of VOCs in exhaled breath. Muscle cells are particularly important, since their release of volatiles during the exertion of an effort contributes considerably to breath concentration profiles. Presently, the cultivation of human skeletal muscle cells is encountering a number of obstacles, necessitating the use of animal muscle cells in in vitro studies. Rat L6 skeletal muscle cells are therefore commonly used as a model for studying the molecular mechanisms of human skeletal muscle differentiation and functions, and facilitate the study of the origin and metabolic fate of the endogenously produced compounds observed in breath and skin emanations. Within this study the production and uptake of VOCs by rat L6 skeletal muscle cells were investigated using gas chromatography with mass spectrometric detection, combined with head-space needle trap extraction as the pre-concentration technique (HS-NTE-GC-MS). Seven compounds were found to be produced, whereas sixteen species were consumed (Wilcoxon signed-rank test, p < 0.05) by the cells being studied. The set of released volatiles included two ketones (2-pentanone and 2-nonanone), two volatile sulphur compounds (dimethyl sulfide and methyl 5-methyl-2-furyl sulphide), and three hydrocarbons (2-methyl 1-propene, n-pentane and isoprene). Of the metabolized species there were thirteen aldehydes (2-propenal, 2-methyl 2-propenal, 2-methyl propanal, 2-butenal, 2-methyl butanal, 3-methyl butanal, n-pentanal, 2-methyl 2-butenal, n-hexanal, benzaldehyde, n-octanal, n-nonanal and n-decanal), two esters (n-propyl propionate and n-butyl acetate), and one volatile sulphur compound (dimethyl disulfide). The possible metabolic pathways leading to the uptake and release of these compounds by L6 cells are proposed and discussed. An analysis of the VOCs showed them to have huge potential for the identification and monitoring of some molecular mechanism and conditions.
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Affiliation(s)
- Paweł Mochalski
- Breath Research Institute of the University of Innsbruck, Rathausplatz 4, A-6850 Dornbirn, Austria
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Kumar V, Palugulla Reddy V, Kokkiligadda A, Shivaji S, Umapathy G. Non-invasive assessment of reproductive status and stress in captive Asian elephants in three south Indian zoos. Gen Comp Endocrinol 2014; 201:37-44. [PMID: 24698789 DOI: 10.1016/j.ygcen.2014.03.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 03/07/2014] [Accepted: 03/13/2014] [Indexed: 11/25/2022]
Abstract
Asian elephants in captivity need immediate attention to be bred so as to meet the increasing demand for captive elephants and to overcome the dependence on supplementing the captive stock with wild animals. Unfortunately, captive breeding programs across the globe have met with limited success and therefore more effort is needed to improve breeding in captivity. Endocrine profiling of reproductive hormones (progestagens and androgens) and the stress hormone (glucocorticoids) could facilitate better management and breeding strategies. In the present study, we investigated reproductive and stress physiology of 12 captive Asian elephants for 10-27 months using a non-invasive method based on steroid analysis of 1700 elephant dung samples. Most of the elephants were cycling regularly. Males during musth showed increased fecal androgen metabolite concentrations and exhibited a slight increase in fecal glucocorticoid metabolite levels. Elephants used in public festivals and processions showed significantly increased in faecal glucocorticoid metabolite levels. The results indicate that captive elephants require periodic health care, better husbandry practices and scientific management for sustainable captive population.
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Affiliation(s)
- Vinod Kumar
- Laboratory for the Conservation of Endangered Species (LaCONES), CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | | | - Adiseshu Kokkiligadda
- Laboratory for the Conservation of Endangered Species (LaCONES), CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Sisinthy Shivaji
- Laboratory for the Conservation of Endangered Species (LaCONES), CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Govindhaswamy Umapathy
- Laboratory for the Conservation of Endangered Species (LaCONES), CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India.
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Soso SB, Koziel JA, Johnson A, Lee YJ, Fairbanks WS. Analytical methods for chemical and sensory characterization of scent-markings in large wild mammals: a review. Sensors (Basel) 2014; 14:4428-65. [PMID: 24603639 PMCID: PMC4003951 DOI: 10.3390/s140304428] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 01/15/2014] [Accepted: 02/25/2014] [Indexed: 01/17/2023]
Abstract
In conjoining the disciplines of "ethology" and "chemistry" the field of "Ethochemistry" has been instituted. Ethochemistry is an effective tool in conservation efforts of endangered species and the understanding of behavioral patterns across all species. Chemical constituents of scent-markings have an important, yet poorly understood function in territoriality, reproduction, dominance, and impact on evolutionary biology, especially in large mammals. Particular attention has recently been focused on scent-marking analysis of great cats (Kalahari leopards (Panthera pardus), puma (Puma concolor) snow leopard (Panthera uncia), African lions (Panthera leo), cheetahs (Acinonyx jubatus), and tigers (Panthera tigris)) for the purpose of conservation. Sensory analyses of scent-markings could address knowledge gaps in ethochemistry. The objective of this review is to summarize the current state-of-the art of both the chemical and sensory analyses of scent-markings in wild mammals. Specific focus is placed on sampling and sample preparation, chemical analysis, sensory analysis, and simultaneous chemical and sensory analyses. Constituents of exocrine and endocrine secretions have been most commonly studied with chromatography-based analytical separations. Odor analysis of scent-markings provides an insight into the animal's sensory perception. A limited number of articles have been published in the area of sensory characterization of scent marks. Simultaneous chemical and sensory analyses with chromatography-olfactometry hyphenation could potentially aid conservation efforts by linking perceived odor, compounds responsible for odor, and resulting behavior.
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Affiliation(s)
- Simone B Soso
- Environmental Science Interdepartmental Graduate Program, Iowa State University, Ames, IA 50011, USA.
| | - Jacek A Koziel
- Environmental Science Interdepartmental Graduate Program, Iowa State University, Ames, IA 50011, USA.
| | - Anna Johnson
- Department of Animal Science, Iowa State University, Ames, IA 50011, USA.
| | - Young Jin Lee
- Department of Chemistry, Iowa State University, Ames, IA 50011, USA.
| | - W Sue Fairbanks
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK 74078, USA.
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Barman P, Yadav MC, Kumar H, Meur SK, Ghosh SK. Gas chromatographic-mass spectrometric analysis of chemical volatiles in buffalo (Bubalus bubalis) urine. Theriogenology 2013; 80:654-8. [PMID: 23876684 DOI: 10.1016/j.theriogenology.2013.06.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 06/08/2013] [Accepted: 06/13/2013] [Indexed: 10/26/2022]
Abstract
Isolation of active fraction and characterization of chemosignals from urine have been attempted in several mammalian species in the recent years. The objective of this study was to identify the urinary volatiles across various reproductive stages of buffalo cow, namely, estrus, diestrus, and pregnancy, and in bull, by chemical extraction followed by gas chromatography-linked mass spectrometry (GC-MS). Urine samples were collected from six buffalo cows at two different phases of estrous cycle, namely, estrus and diestrus. Besides, urinary samples were collected from five pregnant buffalo cows (60-75 days after artificial insemination (AI)) and six adult bulls. Thin-layer chromatography was performed as a preliminary test for qualitative comparison of different compounds extracted by organic solvents. Identification of the urinary compounds was carried out in a gas chromatograph (Perkin Elmer, Autosystem XL) linked to a mass spectrometer (Turbomass). The results of GC-MS analysis indicated the presence of 21 compounds with varying molecular weights and retention time, which were further categorized as diestrus-specific, pregnancy-specific, and bull-specific urinary compounds. No compound, however, could be identified as estrus-specific. We concluded that qualitative differences do exist in estrus, diestrus, and pregnant buffalo cow urine and in bull urine, as evidenced by GC-MS.
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Affiliation(s)
- Purabi Barman
- Department of Veterinary Gynaecology and Obstetrics, College of Veterinary and Animal Sciences, Palampur, Himachal Pradesh, India.
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Archunan G, Rajagopal T. Detection of estrus in Indian blackbuck: behavioural, hormonal and urinary volatiles evaluation. Gen Comp Endocrinol 2013; 181:156-66. [PMID: 23229002 DOI: 10.1016/j.ygcen.2012.11.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 11/15/2012] [Accepted: 11/18/2012] [Indexed: 11/21/2022]
Abstract
The determination of the reproductive status is one of the most important factors for effective wild life conservation and management, and effective use of assisted reproductive techniques like artificial insemination, in vitro fertilization/embryo transfer depends on the knowledge of the basic reproductive physiology. In this context the reproductive status of female blackbucks (Antelope cervicapra L.) was assessed by behaviour and determination, sex steroid hormones in faeces and urinary volatile compounds. The male and female blackbucks exhibited as many as 31 different reproductive/courtship behaviour patterns. Particularly, the males showed a more extensive repertoire: i.e. 23 behavioural patterns by territorial males, 11 by bachelor males and 4 by females. The behaviours such as, mounting, Flehmen, clockwise and anticlockwise movements were significantly higher in male blackbuck when exposed to estrus. By contrast, such courtship behaviours were completely absent in male when exposed to diestrus. It clearly indicates that, the estrus female produces specific chemical cues (pheromone) through urine, which would involve in attracting the conspecifics. In addition, the average faecal oestrogen concentration was significantly higher (p<0.05) during the estrus faecal than the proestrus and diestrus periods. In contrast, the faecal progesterone concentration was significantly higher (p<0.05) during the diestrus faecal sample than that of proestrus and estrus faecal sample. Twenty-eight volatiles are identified, across the three reproductive phases (i.e. proestrus, estrus and diestrus) of sexually mature and prepubertal females. Amongst, the compounds 2-methyl-3-butyn-2-ol, 3,7-dimethylnonane, 3-phenyl-2-propen-1-ol and 2-hydroxybenzoic acid occurred only during estrus which may be considered as marker for detection of estrus which would ultimately help for artificial insemination in captive condition. The findings of the present study suggest that the non-invasive approaches like reproductive behaviours, faecal steroids and estrus-specific urinary volatiles could serve as good indicators for detection of estrus for blackbuck.
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Affiliation(s)
- Govindaraju Archunan
- Centre for Pheromone Technology, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India.
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Yasui S, Konno A, Tanaka M, Idani G, Ludwig A, Lieckfeldt D, Inoue-Murayama M. Personality assessment and its association with genetic factors in captive Asian and African elephants. Zoo Biol 2012; 32:70-8. [PMID: 22996044 DOI: 10.1002/zoo.21045] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 08/01/2012] [Accepted: 08/09/2012] [Indexed: 11/07/2022]
Abstract
Elephants live in a complex society based on matrilineal groups. Management of captive elephants is difficult, partly because each elephant has a unique personality. For a better understanding of elephant well being in captivity, it would be helpful to systematically evaluate elephants' personalities and their underlying biological basis. We sent elephant' personality questionnaires to keepers of 75 elephants. We also used 196 elephant DNA samples to search for genetic polymorphisms in genes expressed in the brain that have been suggested to be related to personality traits. Three genes, androgen receptor (AR), fragile X related mental retardation protein interacting protein (NUFIP2), and acheate-scute homologs 1 (ASH1) contained polymorphic regions. We examined the association of personality with intraspecific genetic variation in 17 Asian and 28 African elephants. The results suggest that the ASH1 genotype was associated with neuroticism in Asian elephants. Subjects with short alleles had lower scores of neuroticism than those with long alleles. This is the first report of an association between a genetic polymorphism and personality in elephants.
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Affiliation(s)
- Saki Yasui
- Wildlife Research Center, Kyoto University, Sakyo, Kyoto, Japan
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Goodwin TE, Broederdorf LJ, Burkert BA, Hirwa IH, Mark DB, Waldrip ZJ, Kopper RA, Sutherland MV, Freeman EW, Hollister-smith JA, Schulte BA. Chemical Signals of Elephant Musth: Temporal Aspects of Microbially-Mediated Modifications. J Chem Ecol 2012; 38:81-7. [DOI: 10.1007/s10886-011-0056-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 10/24/2011] [Accepted: 12/29/2011] [Indexed: 10/14/2022]
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Kaewmanee S, Watanabe G, Keio M, Yamamoto Y, Yamamoto T, Kishimoto M, Nagaoka K, Narushima E, Katayanagi M, Nakao R, Sakurai Y, Morikubo S, Kaneko M, Yoshihara M, Yabe T, Taya K. A surge-like increase in luteinizing hormone preceding musth in a captive bull African elephant (Loxodonta africana). J Vet Med Sci 2010; 73:379-83. [PMID: 21041991 DOI: 10.1292/jvms.10-0259] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study was conducted to determine the correlation between reproductive hormones and musth in a male African elephant. Changes in circulating luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone and immunoreactive (ir-) inhibin and the degree of musth were evaluated for 4 years. LH increased 4 weeks before musth began. The highest concentrations of testosterone and ir-inhibin were observed from April to October. There were positive correlations among testosterone, ir-inhibin and musth behavior. These findings suggested that the surge-like LH in the pre-musth period might stimulate secretion of testosterone and ir-inhibin and thus initiate the musth behavior. This study also suggested that the high LH level before musth might be a useful biomarker for the beginning of the musth season.
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Affiliation(s)
- Saroch Kaewmanee
- Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University
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Rajagopal T, Archunan G, Geraldine P, Balasundaram C. Assessment of dominance hierarchy through urine scent marking and its chemical constituents in male blackbuck Antelope cervicapra, a critically endangered species. Behav Processes 2010; 85:58-67. [PMID: 20547215 DOI: 10.1016/j.beproc.2010.06.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Revised: 05/07/2010] [Accepted: 06/03/2010] [Indexed: 10/19/2022]
Abstract
In ungulates the process of chemical communication by urinary scent marking has been directly related to reproductive dominance, territorial defense and proximity to resources. The differences in the frequency of urine marking and chemical composition of urine of males Antelope cervicapra before, during and after the dominance hierarchy period were assessed. The variations in the urine marking and its chemical profiles of dominant males (n=9), bachelors (n=5) and sub-adult males (n=5) were compared to find out how the dominance hierarchy influences the confined blackbuck herd under semi-natural captive conditions. The frequency of urine marking is significantly higher (p<0.001) in dominant males. Twenty-eight major constituents were identified in the urine of dominant males (before, during and after the dominance hierarchy period), bachelor and sub-adult males. Among these, three specific compounds namely, 3-hexanone (I), 6-methyl-5-hepten-2-one (II) and 4-methyl-3-heptanone (III) were seen only in dominant males urine during the dominance hierarchy period. Based on the behavioural observation and the unique chemical constituents in the urine, it is concluded that the dominant male scent odor suppresses aggression, scent marking, scent production and territorial patrolling activities of subordinate males, through which the dominant male establish their hierarchy and attains success in reproduction.
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Affiliation(s)
- Thangavel Rajagopal
- Center for Pheromone Technology, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli-620 024, Tamil Nadu, India
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Ganswindt A, Muenscher S, Henley M, Henley S, Heistermann M, Palme R, Thompson P, Bertschinger H. Endocrine correlates of musth and the impact of ecological and social factors in free-ranging African elephants (Loxodonta africana). Horm Behav 2010; 57:506-14. [PMID: 20188104 DOI: 10.1016/j.yhbeh.2010.02.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 02/12/2010] [Accepted: 02/17/2010] [Indexed: 11/25/2022]
Abstract
Sexual activity in mature male African elephants is predominantly associated with the occurrence of musth, a state or condition which refers to a set of physical, physiological and behavioral characteristics, including an elevation in androgen levels. Although musth appears to be energetically costly, the degree to which it is associated with changes in adrenal endocrine function (e.g., glucocorticoid output) is still unclear. To investigate the possible effect of musth on adrenocortical function, and the impact of socioecological changes on androgen and glucocorticoid levels, six adult African elephant bulls were followed for 13months in the Kruger National Park, South Africa, and observations and fecal sample collection for endocrine monitoring was carried out about twice weekly. Our data showed that the occurrence of musth was associated with reduced glucocorticoid output, suggesting that musth does not represent a physiological stress mediated by the hypothalamic-pituitary-adrenal axis. This confirms previous findings in captive-housed animals, providing evidence for a suppressive effect of the musth condition on adrenocortical activity. Furthermore, a seasonal effect on androgen and glucocorticoid levels was found, which appears to vary depending on the reproductive status of the animal. The results also indicate a relationship between the presence or absence of social partners and changes in testicular and adrenal endocrine activity. Finally, the data confirm previous findings in captive-housed elephants, that an elevation in androgen concentrations usually occurs before the onset of physical musth signs, and therefore support the idea that the change in androgen levels represents the initial stimulus for the musth condition.
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Affiliation(s)
- André Ganswindt
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
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Yon L, Chen J, Moran P, Lasley B. An analysis of the androgens of musth in the Asian bull elephant (Elephas maximus). Gen Comp Endocrinol 2008; 155:109-15. [PMID: 17466989 DOI: 10.1016/j.ygcen.2007.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 02/06/2007] [Accepted: 03/10/2007] [Indexed: 10/23/2022]
Abstract
During musth in bull elephants, the androgens testosterone (T), dihydrotestosterone (DHT), and androstenedione all increase significantly. Given the unusual endocrine physiology that has been discovered in female elephants, it is also possible that bull elephants produce some unusual androgens. A cell-based androgen receptor assay was used to explore this possibility using two different methods. The first method compared the level of T measured by radioimmunoassay (RIA) with the level of androgen receptor (AR) activity measured in the serum of eight bull elephants during musth and non-musth periods. A ratio was calculated for T/AR activity for non-musth and musth, to determine if there was a change in the ratio between these two states. The second method used HPLC to separate two pooled serum samples (one non-musth and one musth) into fractions using a protocol which separates known androgens into specific, previously identified fractions. Each fraction was then tested with the AR assay to determine the androgenicity of any compounds present. This was done to determine if there were any fractions which had androgenic activity but did not contain any previously identified androgens. Results from the first analysis indicated no change in the T/AR ratio between non-musth and musth states. Clearly whatever active androgens are present during musth, they increase proportionately with T. Findings from the second analysis suggested that the only bioactive androgen present in the serum of non-musth Asian bulls is a low level of T. During musth, the only bioactive androgens detected were T and DHT; of these, T was by far the predominant active androgen present. Taken together, these two analyses suggest that T is by far the predominant active androgen present during musth in Asian bull elephants, and that no previously unidentified bioactive androgen is present.
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Affiliation(s)
- Lisa Yon
- Center for Health and The Environment, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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Bowyer RT, Bleich VC, Manteca X, Whiting JC, Stewart KM. Sociality, Mate Choice, and Timing of Mating in American Bison (Bison bison): Effects of Large Males. Ethology 2007. [DOI: 10.1111/j.1439-0310.2007.01411.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Yon L, Kanchanapangka S, Chaiyabutr N, Stanczyk F, Meepan S, Lasley B. ACTH stimulation in four Asian bull elephants (Elephas maximus): an investigation of androgen sources in bull elephants. Gen Comp Endocrinol 2007; 151:246-51. [PMID: 17350010 DOI: 10.1016/j.ygcen.2007.01.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 01/17/2007] [Accepted: 01/23/2007] [Indexed: 11/21/2022]
Abstract
The phenomenon of musth is a very stressful event, both behaviorally and physiologically. An ACTH stimulation test was conducted in four adult Asian bull elephants to investigate the possibility that the classical hypothalamic-pituitary-adrenal (HPA) axis is active during musth, resulting in an increase in adrenally produced steroids. Serum cortisol, testosterone (T), androstenedione (A4), androstenediol (A5), and dehydroepiandrosterone (DHEA) were measured. Cortisol increased 3-10 times above baseline in response to ACTH stimulation, and DHEA doubled. A4 and A5 were erratic, while testosterone decreased significantly in all bulls. The pattern of results suggests that the adrenal steroid increase which occurs during musth results from some mechanism other than the classical HPA axis.
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Affiliation(s)
- Lisa Yon
- Center for Health and the Environment, University of California, One Shields Ave., Davis, CA 95616, USA
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Yon L, Kanchanapangka S, Chaiyabutr N, Meepan S, Stanczyk FZ, Dahl N, Lasley B. A longitudinal study of LH, gonadal and adrenal steroids in four intact Asian bull elephants (Elephas maximus) and one castrate African bull (Loxodonta africana) during musth and non-musth periods. Gen Comp Endocrinol 2007; 151:241-5. [PMID: 17350012 DOI: 10.1016/j.ygcen.2007.01.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 01/17/2007] [Accepted: 01/23/2007] [Indexed: 11/16/2022]
Abstract
During their annual musth cycle, adult African and Asian bull elephants have increased gonadal androgens (testosterone [T], dihydrotestosterone [DHT], androstenedione [A4]). Because musth is a physiologically and psychologically stressful time, this study was conducted to investigate whether the adrenal glands (stimulated by stress) increase production of both glucocorticoids and androgens during musth. Weekly serum samples were taken for 11-15 months from four intact adult Asian bull elephants, and from a castrate African bull elephant who exhibits musth. Testosterone, androstenediol (A5), A4, luteinizing hormone (LH), cortisol, and dehydroepiandrosterone (DHEA) were measured in each sample. In three of the four intact bulls, all hormones measured increased during musth. Adrenal androgens were strongly correlated with LH and testicular androgens, though not to cortisol. None of the hormones measured in the castrate bull increased during his musth cycles. While the significance of adrenal activity in the elephant during musth has yet to be determined, this study provides evidence that the adrenal gland actively produces both glucocorticoids and androgens during musth in the Asian elephant.
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Affiliation(s)
- Lisa Yon
- Center for Health and the Environment, University of California, One Shields Ave., Davis, CA 95616, USA
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Schulte BA, Freeman EW, Goodwin TE, Hollister-Smith J, Rasmussen LEL. Honest signalling through chemicals by elephants with applications for care and conservation. Appl Anim Behav Sci 2007. [DOI: 10.1016/j.applanim.2006.05.035] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Achiraman S, Archunan G. 1-Iodo-2methylundecane, a putative estrus-specific urinary chemo-signal of female mouse (Mus musculus). Theriogenology 2006; 66:1913-20. [PMID: 16780940 DOI: 10.1016/j.theriogenology.2006.05.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Revised: 05/05/2006] [Accepted: 05/07/2006] [Indexed: 11/25/2022]
Abstract
The present study was designed to identify the urinary volatiles across various reproductive stages of female mice in order to detect estrus-specific chemical signal. The urine of adult female mice were extracted with dichloromethane (1:1 ratio, v/v) and analyzed by gas chromatography linked mass-spectrometry (GC-MS). Numerous compounds were identified during estrus cycle of female mice urine. Among these, the compounds, namely, isocroctylhydrazine, 4-methyl-2-heptanone and auzulene were specific to proestrus stage and the compounds, 1-H-cyclopop-e.auzulene, caryophyllene, copanene were specific to estrus stage. However, the compound, 1-iodo-2methyl undecane (1I2MU) was observed both in proestrus and estrus phases and was absent in all other phases. The volatile signal produced at the end of proestrus and the beginning of estrus phase appears to be behaviourally important in the attraction of males. Moreover, the behaviour assay revealed that the compound, 1I2MU, is involved in attracting the male mice. This result concludes that the 1-iodo-2methyl undecane is considered as a putative estrus-specific chemo-signal.
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Affiliation(s)
- Shanmugam Achiraman
- Department of Animal Science, Bharathidasan University, Tiruchirappalli 620 024, India
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Wang DKW, Austin CC. Determination of complex mixtures of volatile organic compounds in ambient air: canister methodology. Anal Bioanal Chem 2006; 386:1099-120. [PMID: 16775705 DOI: 10.1007/s00216-006-0466-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2005] [Revised: 03/31/2006] [Accepted: 04/03/2006] [Indexed: 10/24/2022]
Abstract
Canister methodology is applicable to 150 polar and nonpolar VOCs found in ambient air from parts-per-billion by volume (ppbv) to parts-per-million (ppmv) levels, and has been validated at parts-per-trillion (pptv) levels for a subset of these analytes. This article is a detailed review of techniques related to the collection of volatile organic compounds (VOCs) in evacuated Summa and fused-silica-lined canisters, and their analysis by gas chromatography/mass spectrometry (GC/MS). Emphasis is placed on canister cleaning, VOC stability in canisters, sample dilution, water management, and VOC cryogenic and sorbent preconcentration methods. A wide range of VOC preconcentration and water management methods are identified from the literature, and their relative merits and disadvantages are discussed. Examples of difficulties that commonly arise when processing canister samples are illustrated, and solutions to these problems are provided.
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Affiliation(s)
- D K W Wang
- Environmental Technology Centre, Environment Canada, 335 River Road, Ottawa, K1A 0H3, Canada.
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Abstract
Musth in male elephants is an annual period of heightened sexual activity and aggression that is linked to physical, sexual and social maturation. It is mediated by the release of chemical signals such as the pheromone frontalin, which exists in two chiral forms (molecular mirror images, or enantiomers). Here we show that enantiomers of frontalin are released by Asian elephants in a specific ratio that depends on the animal's age and stage of musth, and that different responses are elicited in male and female conspecifics when the ratio alters. This precise control of communication by molecular chirality offers insight into societal interactions in elephants, and may be useful in implementing new conservation protocols.
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Affiliation(s)
- David R Greenwood
- HortResearch, Mount Albert Research Centre, Private Bag 92-169, Auckland, New Zealand
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Rasmussen LEL, Wittemyer G. Chemosignalling of musth by individual wild African elephants (Loxodonta africana): implications for conservation and management. Proc Biol Sci 2002; 269:853-60. [PMID: 11958718 PMCID: PMC1690966 DOI: 10.1098/rspb.2001.1933] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Elephants have extraordinary olfactory receptive equipment, yet this sensory system has been only minimally investigated in wild elephants. We present an in-depth study of urinary chemical signals emitted by individual, behaviourally characterized, wild male African elephants, investigating whether these compounds were the same, accentuated, or diminished in comparison with captive individuals. Remarkably, most emitted chemicals were similar in captive and wild elephants with an exception traced to drought-induced dietary cyanates among wild males. We observed developmental changes predominated by the transition from acids and esters emitted by young males to alcohols and ketones released by older males. We determined that the ketones (2-butanone, acetone and 2-pentanone, and 2-nonanone) were considerably elevated during early musth, musth and late musth, respectively, suggesting that males communicate their condition via these compounds. The similarity to compounds released during musth by Asian male elephants that evoke conspecific bioresponses suggests the existence of species-free 'musth' signals. Our innovative techniques, which allow the recognition of precise sexual and musth states of individual elephants, can be helpful to managers of both wild and captive elephants. Such sampling may allow the more accurate categorization of the social and reproductive status of individual male elephants.
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Affiliation(s)
- L E L Rasmussen
- Department of Biochemistry and Molecular Biology, OGI School of Science and Engineering, Oregon Health & Science University, 20 000 N.W. Walker Road, Beaverton, OR 97006-8921, USA.
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Abstract
Male Asian elephants in musth--an annual period of heightened sexual activity and intensified aggression--broadcast odoriferous, behaviourally influential messages from secretions of the temporal gland. From our observations in the wild, together with instantaneous chemical sampling and captive-elephant playback experiments, we have discovered that young, socially immature males in musth signal their naivety by releasing honey-like odours to avoid conflict with adult males, whereas older musth males broadcast malodorous combinations to deter young males, facilitating the smooth functioning of male society. As elephant--human conflicts can upset this equilibrium, chemically modulating male behaviour may be one way to help the conservation of wild elephants.
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Affiliation(s)
- L E L Rasmussen
- Department of Biochemistry and Molecular Biology, OGI School of Science and Engineering, Oregon Health and Science University, Beaverton, Oregon 97006-8921, USA.
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Affiliation(s)
- Bruce A. Schulte
- Department of Biology, Georgia Southern University, Statesboro, Georgia
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