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Vermeulen MM, Fritz H, Strauss WM, Hetem RS, Venter JA. Seasonal activity patterns of a Kalahari mammal community: Trade-offs between environmental heat load and predation pressure. Ecol Evol 2024; 14:e11304. [PMID: 38628919 PMCID: PMC11019135 DOI: 10.1002/ece3.11304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 03/24/2024] [Accepted: 04/04/2024] [Indexed: 04/19/2024] Open
Abstract
Mammals in arid zones have to trade off thermal stress, predation pressure, and time spent foraging in a complex thermal landscape. We quantified the relationship between the environmental heat load and activity of a mammal community in the hot, arid Kalahari Desert. We deployed miniature black globe thermometers within the existing Snapshot Safari camera trap grid on Tswalu Kalahari Reserve, South Africa. Using the camera traps to record species' activity throughout the 24-h cycle, we quantified changes in the activity patterns of mammal species in relation to heat loads in their local environment. We compared the heat load during which species were active between two sites with differing predator guilds, one where lion (Panthera leo) biomass dominated the carnivore guild and the other where lions were absent. In the presence of lion, prey species were generally active under significantly higher heat loads, especially during the hot and dry spring. We suggest that increased foraging under high heat loads highlights the need to meet nutritional requirements while avoiding nocturnal activity when predatory pressures are high. Such a trade-off may become increasingly costly under the hotter and drier conditions predicted to become more prevalent as a result of climate change within the arid and semi-arid regions of southern Africa.
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Affiliation(s)
- Mika M. Vermeulen
- Department of Conservation ManagementNelson Mandela UniversityGeorgeWestern CapeSouth Africa
| | - Hervé Fritz
- Sustainability Research UnitNelson Mandela UniversityGeorgeWestern CapeSouth Africa
- International Research LaboratoryREHABS, CNRS – Université de Lyon 1 – Nelson Mandela UniversityGeorgeWestern CapeSouth Africa
| | - W. Maartin Strauss
- School of Biological SciencesUniversity of CanterburyChristchurchNew Zealand
| | - Robyn S. Hetem
- School of Biological SciencesUniversity of CanterburyChristchurchNew Zealand
- School of Animal, Plant and Environmental SciencesUniversity of the WitwatersrandJohannesburgGautengSouth Africa
| | - Jan A. Venter
- Department of Conservation ManagementNelson Mandela UniversityGeorgeWestern CapeSouth Africa
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Jin Z, Guo L, Shu H, Qi J, Li Y, Xu B, Zhang W, Wang K, Wang W. Behavior Classification and Analysis of Grazing Sheep on Pasture with Different Sward Surface Heights Using Machine Learning. Animals (Basel) 2022; 12:ani12141744. [PMID: 35883291 PMCID: PMC9311692 DOI: 10.3390/ani12141744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/03/2022] [Accepted: 07/05/2022] [Indexed: 11/16/2022] Open
Abstract
Behavior classification and recognition of sheep are useful for monitoring their health and productivity. The automatic behavior classification of sheep by using wearable devices based on IMU sensors is becoming more prevalent, but there is little consensus on data processing and classification methods. Most classification accuracy tests are conducted on extracted behavior segments, with only a few trained models applied to continuous behavior segments classification. The aim of this study was to evaluate the performance of multiple combinations of algorithms (extreme learning machine (ELM), AdaBoost, stacking), time windows (3, 5 and 11 s) and sensor data (three-axis accelerometer (T-acc), three-axis gyroscope (T-gyr), and T-acc and T-gyr) for grazing sheep behavior classification on continuous behavior segments. The optimal combination was a stacking model at the 3 s time window using T-acc and T-gyr data, which had an accuracy of 87.8% and a Kappa value of 0.836. It was applied to the behavior classification of three grazing sheep continuously for a total of 67.5 h on pasture with three different sward surface heights (SSH). The results revealed that the three sheep had the longest walking, grazing and resting times on the short, medium and tall SHH, respectively. These findings can be used to support grazing sheep management and the evaluation of production performance.
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Affiliation(s)
- Zhongming Jin
- Agricultural Information Institute, Chinese Academy of Agriculture Sciences, Beijing 100086, China; (Z.J.); (H.S.); (Y.L.); (B.X.); (W.Z.); (K.W.)
| | - Leifeng Guo
- Agricultural Information Institute, Chinese Academy of Agriculture Sciences, Beijing 100086, China; (Z.J.); (H.S.); (Y.L.); (B.X.); (W.Z.); (K.W.)
- Correspondence: (L.G.); (W.W.)
| | - Hang Shu
- Agricultural Information Institute, Chinese Academy of Agriculture Sciences, Beijing 100086, China; (Z.J.); (H.S.); (Y.L.); (B.X.); (W.Z.); (K.W.)
- AgroBioChem/TERRA, Precision Livestock and Nutrition Unit, Gembloux Agro-Bio Tech, University of Liège, 5030 Gembloux, Belgium
| | - Jingwei Qi
- College of Animal Science, Inner Mongolia Agricultural University, Hohhot 010018, China;
| | - Yongfeng Li
- Agricultural Information Institute, Chinese Academy of Agriculture Sciences, Beijing 100086, China; (Z.J.); (H.S.); (Y.L.); (B.X.); (W.Z.); (K.W.)
| | - Beibei Xu
- Agricultural Information Institute, Chinese Academy of Agriculture Sciences, Beijing 100086, China; (Z.J.); (H.S.); (Y.L.); (B.X.); (W.Z.); (K.W.)
| | - Wenju Zhang
- Agricultural Information Institute, Chinese Academy of Agriculture Sciences, Beijing 100086, China; (Z.J.); (H.S.); (Y.L.); (B.X.); (W.Z.); (K.W.)
| | - Kaiwen Wang
- Agricultural Information Institute, Chinese Academy of Agriculture Sciences, Beijing 100086, China; (Z.J.); (H.S.); (Y.L.); (B.X.); (W.Z.); (K.W.)
- Information Technology Group, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
| | - Wensheng Wang
- Agricultural Information Institute, Chinese Academy of Agriculture Sciences, Beijing 100086, China; (Z.J.); (H.S.); (Y.L.); (B.X.); (W.Z.); (K.W.)
- Correspondence: (L.G.); (W.W.)
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Mavrovouna V, Penacchio O, Allen WL. Orienting to the sun improves camouflage for bilaterally symmetrical prey. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Here, we investigate the camouflage consequences of animal orientation behaviour. Shadows can be a conspicuous cue to the presence of prey. For bilaterally symmetrical animals, light field modelling indicates that camouflage will be improved when an animal orients its longitudinal axis directly towards or away from the sun, because the appearance of shadows is minimized. We test this prediction with a field predation experiment, in which wild birds hunt for artificial camouflaged prey oriented with the longitudinal axis either parallel or perpendicular to the sun. We find that prey oriented parallel to the sun are 3.93 times more likely to survive than prey oriented perpendicular to the sun. This result demonstrates the strong orientation dependence of camouflage. Given the dramatic difference in survival of prey with different orientations, we suggest that camouflage should be investigated as an important determinant of the positional behaviour of animals.
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Affiliation(s)
- Veronica Mavrovouna
- Department of Biosciences, Swansea University, Singleton Campus, Swansea SA2 8PP, UK
| | - Olivier Penacchio
- School of Psychology and Neuroscience, University of St Andrews, South Street, St Andrews, Fife KY16 9JP, UK
| | - William L Allen
- Department of Biosciences, Swansea University, Singleton Campus, Swansea SA2 8PP, UK
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Botha A, Lease HM, Fuller A, Mitchell D, Hetem RS. Biologging subcutaneous temperatures to detect orientation to solar radiation remotely in savanna antelope. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2019; 331:267-279. [PMID: 31033258 DOI: 10.1002/jez.2267] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/19/2019] [Accepted: 03/20/2019] [Indexed: 11/07/2022]
Abstract
Observations of animal thermoregulatory behavior are labor-intensive, and human presence may disturb the normal behavior of the animal. Therefore, we investigated whether a remote biologging technique could be used to detect orientation to solar radiation in savanna antelope. We predicted that when a mammal was orientated perpendicular to solar radiation, the subcutaneous temperature on the side of the body facing the sun would be greater than that on the opposite side, whereas when the mammal was orientated parallel to solar radiation, subcutaneous temperatures on both sides would be similar. A pilot study showed that the difference between left- and right-side temperatures under a pelt reflected orientation to solar radiation if a pelt-covered cylinder had been orientated for 15 min or longer. In addition, the rate of change in temperature difference could detect orientation that had changed within the previous 5 min. We implanted temperature-sensitive data loggers subcutaneously into the flanks of eight black (Connochaetes gnu) and eight blue (Connochaetes taurinus) wildebeest. By incorporating both the rate of change and subcutaneous temperature differences and excluding times when wildebeest were lying down, our predictions correctly matched behavioral observations of wildebeest orientation to solar radiation 71% of the time. Our technique tended to fail when wildebeest were lying down, wind speeds were high and the sun was overhead. But those are conditions in which the benefits of manipulating orientation to solar radiation is of diminishing importance to a free-living mammal. Therefore, subcutaneous temperatures provide physiologically relevant information on the importance of solar radiation to mammals.
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Affiliation(s)
- Arista Botha
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Hilary M Lease
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Physiology, University of Arizona, Tucson, Arizona
| | - Andrea Fuller
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,School of Human Sciences, University of Western Australia, Perth, Australia
| | - Robyn S Hetem
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,School of Animal, Plant and Environmental Sciences, Faculty of Science, University of the Witwatersrand, Johannesburg, South Africa
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Thaker M, Gupte PR, Prins HHT, Slotow R, Vanak AT. Fine-Scale Tracking of Ambient Temperature and Movement Reveals Shuttling Behavior of Elephants to Water. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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6
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Thermoregulatory behavior and orientation preference in bearded dragons. J Therm Biol 2017; 69:171-177. [DOI: 10.1016/j.jtherbio.2017.07.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 07/18/2017] [Accepted: 07/19/2017] [Indexed: 11/15/2022]
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7
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Pleskač L, Hart V, Nováková P, Painter MS. Spatial orientation of foraging corvids consistent with spontaneous magnetic alignment responses observed in a variety of free-roaming vertebrates. FOLIA ZOOLOGICA 2017. [DOI: 10.25225/fozo.v66.i2.a3.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Lukáš Pleskač
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Kamýcká 129, 165 21 Praha 6, Czech Republic;, , ,
| | - Vlastimil Hart
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Kamýcká 129, 165 21 Praha 6, Czech Republic;, , ,
| | - Petra Nováková
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Kamýcká 129, 165 21 Praha 6, Czech Republic;, , ,
| | - Michael S. Painter
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Kamýcká 129, 165 21 Praha 6, Czech Republic;, , ,
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Zakari FO, Ayo JO, Rekwot PI, Kawu MU. Effects of age and season on haematological parameters of donkeys during the rainy and cold-dry seasons. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2015; 59:1813-1824. [PMID: 25860334 DOI: 10.1007/s00484-015-0989-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Revised: 03/19/2015] [Accepted: 03/23/2015] [Indexed: 06/04/2023]
Abstract
The aim of the study was to investigate the effects of age and season on haematological parameters of donkeys at rest during the rainy and cold-dry seasons. Thirty healthy donkeys divided into three groups based on their age served as the subjects. During each season, blood sample was collected from each donkey thrice, 2 weeks apart, for haematological analysis, and the dry-bulb temperature (DBT), relative humidity (RH) and temperature-humidity index (THI) were obtained thrice each day during the experimental period using standard procedures. During the rainy season, the mean DBT (33.05 ± 0.49 °C), RH (73.63 ± 1.09 %) and THI (84.39 ± 0.71) were higher (P < 0.0001) than the corresponding values of 24.00 ± 0.44 °C, 36.80 ± 0.92 % and 64.80 ± 0.62, during the cold-dry season. Packed cell volume (PCV), erythrocyte count [red blood cell (RBC)], haemoglobin concentration (Hb), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), platelet count (PLT), leucocyte count [white blood cell (WBC)], lymphocyte count (LYM) and neutrophil/lymphocyte ratio (N/L) were higher (P < 0.05) in adults than foals during the rainy season. The MCV, MCH, WBC, NEU, LYM and PLT of adult and yearling donkeys were higher (P < 0.05) during the rainy than the cold-dry season. The PCV, RBC, Hb, MCV, MCH, and NEU of foals were higher in the rainy than the cold-dry season. The N/L of adult and foal donkeys were higher (P < 0.05) in the rainy than in the cold-dry season. In conclusion, PCV, RBC, Hb and LYM were considerably higher in foals than yearlings or adults during the rainy season, while erythrocytic indices and platelet counts were higher in adults or yearlings than in foals in both seasons. Erythrocytic indices, PLT and N/L were higher in the rainy than the cold-dry season in adults, yearlings and foals.
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Affiliation(s)
- Friday Ocheja Zakari
- Department of Physiology, Faculty of Veterinary Medicine, Ahmadu Bello University, PMB 1045, Zaria, Nigeria.
| | - Joseph Olusegun Ayo
- Department of Physiology, Faculty of Veterinary Medicine, Ahmadu Bello University, PMB 1045, Zaria, Nigeria
| | - Peter Ibrahim Rekwot
- National Animal Production Research Institute, Ahmadu Bello University, PMB 1096, Zaria, Nigeria
| | - Mohammed Umar Kawu
- Department of Physiology, Faculty of Veterinary Medicine, Ahmadu Bello University, PMB 1045, Zaria, Nigeria
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Milne R, Cunningham SJ, Lee ATK, Smit B. The role of thermal physiology in recent declines of birds in a biodiversity hotspot. CONSERVATION PHYSIOLOGY 2015; 3:cov048. [PMID: 27293732 PMCID: PMC4778484 DOI: 10.1093/conphys/cov048] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 09/26/2015] [Accepted: 10/01/2015] [Indexed: 06/06/2023]
Abstract
We investigated whether observed avian range contractions and population declines in the Fynbos biome of South Africa were mechanistically linked to recent climate warming. We aimed to determine whether there were correlations between preferred temperature envelope, or changes in temperature within species' ranges, and recent changes in range and population size, for 12 Fynbos-resident bird species, including six that are endemic to the biome. We then measured the physiological responses of each species at air temperatures ranging from 24 to 42°C to determine whether physiological thermal thresholds could provide a mechanistic explanation for observed population trends. Our data show that Fynbos-endemic species occupying the coolest regions experienced the greatest recent reductions in range and population size (>30% range reduction between 1991 and the present). In addition, species experiencing the largest increases in air temperature within their ranges showed the greatest declines. However, evidence for a physiological mechanistic link between warming and population declines was equivocal, with only the larger species showing low thermal thresholds for their body mass, compared with other birds globally. In addition, some species appear more vulnerable than others to air temperatures in their ranges above physiological thermal thresholds. Of these, the high-altitude specialist Cape rockjumper (Chaetops frenatus) seems most at risk from climate warming. This species showed: (i) the lowest threshold for increasing evaporative water loss at high temperatures; and (ii) population declines specifically in those regions of its range recording significant warming trends. Our findings suggest that caution must be taken when attributing causality explicitly to thermal stress, even when population trends are clearly correlated with rates of warming. Studies explicitly investigating the mechanisms underlying such correlations will be key to appropriate conservation planning.
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Affiliation(s)
- Robyn Milne
- Percy FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa
| | - Susan J Cunningham
- Percy FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa
| | - Alan T K Lee
- Percy FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa
- Birds and Environmental Change Programme, Climate Change and Adaptation Division, South African National Biodiversity Institute, Claremont 7735, South Africa
| | - Ben Smit
- Centre for African Conservation Ecology, Department of Zoology, Nelson Mandela Metropolitan University, Port Elizabeth 6031, South Africa
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Spengler D, Strobel H, Axt H, Voigt K. [Water requirements, water supply and thermoregulation in small ruminants in pasture-based husbandry systems]. Tierarztl Prax Ausg G Grosstiere Nutztiere 2015; 43:49-59; quiz 60. [PMID: 25634729 DOI: 10.15653/tpg-140781] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 11/15/2014] [Indexed: 11/22/2022]
Abstract
Water is an essential source of life and is available to animals as free water, water content of feed, film water (e. g. dew) and metabolic water. The water requirements of small ruminants are influenced by the type of feed, climate, stage of production, type and length of the fleece or hair coat, husbandry factors and the general health of the animal. Differences in water metabolism, drinking behaviour and the efficiency of temperature regulation are further influenced by species, breed, production type, husbandry system, acclimatisation and adaptation. Small ruminants have been, and are still predominantly kept in extensive husbandry systems. They are therefore genetically and phenotypically well adapted to these conditions and possess a range of physiological and behavioural mechanisms to deal with adverse and suboptimal weather conditions. Regarding animal welfare, there is considerable debate in the discussion and assessment of what constitutes a sufficient water supply for small ruminants under different husbandry conditions, often involving differences between theoretical demands and practical experience. This publication reviews and summarises the current literature regarding water requirements, water metabolism and thermoregulatory mechanisms of small ruminants to provide the basis for an informed assessment of extensive husbandry systems in terms of compliance with animal-welfare requirements.
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Affiliation(s)
- D Spengler
- Dr. Dieter Spengler, Am Heidengraben 6, 79199 Kirchzarten, E-Mail:
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Zakari FO, Ayo JO, Rekwot PI, Kawu MU. Effect of age, sex, physical activity and meteorological factors on haematological parameters of donkeys ( Equus asinus). COMPARATIVE CLINICAL PATHOLOGY 2014; 25:1265-1272. [PMID: 27818622 PMCID: PMC5069348 DOI: 10.1007/s00580-014-2026-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 10/14/2014] [Indexed: 01/22/2023]
Abstract
The review examines the role of blood in homeostasis, diagnosis and treatment of disease as influenced by meteorological stress factors, age, sex and physical activity of the donkeys. Haematological parameters play a crucial role in clinical diagnosis of infectious and parasitic diseases, in assessing the responses of donkeys to treatment and in prevention of diseases. The changes in blood values are important in evaluating the responses of the animals to various physiologic conditions. In conclusion, haematological values of donkeys are largely influenced by age, sex, physical factors of the environment and physical activity, and consideration of the factors will aid accurate diagnosis and therapeutic evaluation of equine diseases.
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Affiliation(s)
- Friday Ocheja Zakari
- Department of Physiology, Faculty of Veterinary Medicine, Ahmadu Bello University, PMB 1045, Zaria, Nigeria
| | - Joseph Olusegun Ayo
- Department of Physiology, Faculty of Veterinary Medicine, Ahmadu Bello University, PMB 1045, Zaria, Nigeria
| | - Peter Ibrahim Rekwot
- National Animal Production Research Institute (NAPRI), Ahmadu Bello University, PMB 1096, Zaria, Nigeria
| | - Mohammed Umar Kawu
- Department of Physiology, Faculty of Veterinary Medicine, Ahmadu Bello University, PMB 1045, Zaria, Nigeria
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Black wildebeest seek shade less and use solar orientation behavior more than do blue wildebeest. J Therm Biol 2014; 45:150-6. [PMID: 25436964 DOI: 10.1016/j.jtherbio.2014.08.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 08/25/2014] [Accepted: 08/25/2014] [Indexed: 11/20/2022]
Abstract
Many ungulates, including wildebeest, seek shade and orient their bodies relative to incoming solar radiation in order to reduce environmental heat loads. Blue (Connochaetes taurinus) and black wildebeest (Connochaetes gnou), which co-exist artificially in some reserves in South Africa, are thought to adopt different thermoregulatory behaviors to mitigate high environmental heat loads. However, whether or not blue and black wildebeest use different behaviors to reduce heat loads in regions where they co-occur has never previously been examined. We compared the shade seeking and solar orientation behavior of free-ranging blue and black wildebeest in summer at three locations in South Africa where both species co-occur. We found that blue wildebeest exhibited more shade seeking behavior than did black wildebeest at all times of day, at all study sites. Black wildebeest remained in the sun but were more likely than blue wildebeest to orient their bodies parallel to the sun at all study sites, a behavior which reduces the amount of surface area exposed to incoming radiation. Black wildebeest were most likely to employ parallel solar orientation during the hottest times of the day when the sun was not directly overhead (i.e., solar noon ± 1 hour). We thus demonstrate that co-occurring blue and black wildebeest use different thermoregulatory behaviors to reduce high heat loads. It is possible that the lack of shade in the historical distribution of black wildebeest led to selective pressure for reliance on solar orientation. Differences in thermoregulatory behavior can affect species-specific heat loads, habitat use, body mass, fitness and grazing activity. Such differences may also allow blue and black wildebeest to inhabit separate microclimates within the same habitat, provided there is sufficient heterogeneity in vegetation structure, potentially facilitating reproductive isolation.
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Wintering birds avoid warm sunshine: predation and the costs of foraging in sunlight. Oecologia 2013; 174:713-21. [DOI: 10.1007/s00442-013-2804-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 10/03/2013] [Indexed: 10/26/2022]
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Begall S, Malkemper EP, Červený J, Němec P, Burda H. Magnetic alignment in mammals and other animals. Mamm Biol 2013. [DOI: 10.1016/j.mambio.2012.05.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Physiological and haematological indices suggest superior heat tolerance of white-coloured West African Dwarf sheep in the hot humid tropics. Trop Anim Health Prod 2012; 45:157-65. [PMID: 22639037 DOI: 10.1007/s11250-012-0187-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2012] [Indexed: 10/28/2022]
Abstract
Coat colour contributes to physiological adaptation in mammals and mediates response to thermal stress. Twenty-four adult West African Dwarf sheep of both sexes and with different coat colour types were used in this study. We measured rectal temperature (RT), respiratory rate (RR) and pulse rate (PR) before sunrise and sunset during the late dry season (January-March) and early rainy season (April-June) as well as packed cell volume (PCV), red blood cell (RBC) count, white blood cell (WBC) count, plasma sodium (Na(+)) and potassium (K(+)). Animals with black coat colour had the highest (P < 0.05) mean values of 38.92 ± 0.03 °C, 65.09 ± 1.06 breaths/min, 81.35 ± 0.78 beats/min, 1.70 ± 0.01 for RT, RR, PR and heat stress index (HSI), respectively, followed by brown mouflon and brown with extensive white, while the Badger Face coloured sheep had the least mean values. There were significant (P < 0.05) differences between male and female sheep for RT, RR, PR and HSI. Season had a significant (P < 0.05) effect on RT, RR, PR and HSI. Coat colour and sex also significantly (P < 0.01) affected RBC, WBC, Na(+) and K(+). Seasonal variation (P < 0.05) in all the blood parameters was observed, with the exception of PCV. Interaction effect of coat colour and sex was significant (P < 0.05) on RT and HSI. Correlation coefficients among the measured traits ranged from positive to negative values. These results indicate that selection of white-coloured sheep to attenuate heat stress is desirable in the hot humid tropics.
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