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Riordan K, Thometz NM, Batac FI, Nicholson TE, Liwanag HEM. Effects of ontogeny and oiling on the thermal function of southern sea otter ( Enhydra lutris nereis) fur. Conserv Physiol 2023; 11:coad095. [PMID: 38107463 PMCID: PMC10724463 DOI: 10.1093/conphys/coad095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 11/08/2023] [Accepted: 11/28/2023] [Indexed: 12/19/2023]
Abstract
During the evolution of most marine mammals, fur as an insulator has been replaced with more buoyant, energy storing and streamlining blubber. By contrast, the sea otter (Enhydra lutris) relies on insulation from its dense, air-trapping pelage, which differs morphologically between natal and adult stages. In this study, we investigated the ontogenetic changes in thermal function of southern sea otter (Enhydra lutris nereis) pelts in air, in water, and when saturated with crude oil. Pelt thermal conductivity, thickness, and thermal resistance were measured for six age classes: neonate (<1 month), small pup (1-2 months), large pup (3-5 months), juvenile (6 months-1 year), subadult (1-3 years), and adult (4-9 years). Thermal conductivity was significantly higher for pelts in air than in water, with oiled pelts exhibiting the highest values (P < 0.001). Oiled pelts had the lowest thermal resistance, which suggests that regardless of age, all sea otters are vulnerable to the effects of oiling (P < 0.001). To scale up our laboratory findings, we used a volume-specific geometric model of conductive heat transfer for a simplified sea otter body, representing all tested age classes and treatments. Neonates, small pups, and large pups are more vulnerable to the effects of oiling compared with older age classes (P < 0.0001) due to a higher surface area-to-volume ratio. These results are consistent with the known thermal conductance values for adult sea otter pelts, yet this is the first time such thermal differences have been demonstrated in young otters. Overall, body size and age play a more important role in the thermal abilities of sea otters than previously thought.
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Affiliation(s)
- Kate Riordan
- Department of Biological Sciences, California Polytechnic State University San Luis Obispo, 1 Grand Ave, San Luis Obispo, CA 93407, USA
| | - Nicole M Thometz
- Department of Biology, University of San Francisco, 2130 Fulton Street, San Francisco, CA 94117, USA
| | - Francesca I Batac
- California Department of Fish and Wildlife, Marine Wildlife Veterinary Care and Research Center, 151 McAllister Way, Santa Cruz, CA 95060, USA
| | | | - Heather E M Liwanag
- Department of Biological Sciences, California Polytechnic State University San Luis Obispo, 1 Grand Ave, San Luis Obispo, CA 93407, USA
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2
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Riordan K, Dean AE, Adema P, Thometz NM, Batac FI, Liwanag HEM. Ontogenetic changes in southern sea otter (Enhydra lutris nereis) fur morphology. J Morphol 2023; 284:e21624. [PMID: 37585225 DOI: 10.1002/jmor.21624] [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] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/03/2023] [Accepted: 07/15/2023] [Indexed: 08/17/2023]
Abstract
Many animals exhibit morphological changes across ontogeny associated with adaptations to their environment. Sea otters (Enhydra lutris) have the densest fur of any animal, which is composed of guard hairs, intermediate hairs, and underhairs. Sea otters live in cold water environments, and their fur traps a layer of air to remain properly insulated, due to morphological adaptations that allow the hairs to trap air when submerged. When a sea otter is born, it has a natal pelage which it will eventually molt and replace with a pelt resembling the adult pelage. Past studies have investigated the morphology and hair density of adult sea otter fur, but these characteristics have not been measured for other age classes, including for the natal pelage. This study quantified ontogenetic changes in hair morphology of southern sea otter (E. lutris nereis) pelts. We measured guard hair length and circularity, shape of cuticular scales on guard hairs and underhairs, and overall hair density for sea otter pelts across six age classes: neonate (<1 month), small pup (1-2 months), large pup (3-5 months), juvenile (6 months-1 year), subadult (1-3 years), and adult (4-9 years). Neonate and small pup pelts had significantly longer guard hairs than older age classes. Natal pelage guard hairs were similarly shaped but smaller in diameter than adult guard hairs. Hairs of the natal pelage had similar cuticular scale patterns as adult hairs, indicating the importance of this structure for the function of the fur. Natal pelage had a lower hair density than the pelage of older age classes, with the adult pelage exhibiting the highest hair density. Overall, the morphological differences between natal and adult pelage in sea otters suggest functional differences that may make sea otter pups more vulnerable to heat loss.
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Affiliation(s)
- Kate Riordan
- Department of Biological Sciences, California Polytechnic State University San Luis Obispo, San Luis Obispo, California, USA
| | - Annika E Dean
- Department of Biological Sciences, California Polytechnic State University San Luis Obispo, San Luis Obispo, California, USA
| | - Payton Adema
- Department of Biological Sciences, California Polytechnic State University San Luis Obispo, San Luis Obispo, California, USA
| | - Nicole M Thometz
- Department of Biology, University of San Francisco, San Francisco, California, USA
| | - Francesca I Batac
- California Department of Fish and Wildlife, Marine Wildlife Veterinary Care and Research Center, Santa Cruz, California, USA
| | - Heather E M Liwanag
- Department of Biological Sciences, California Polytechnic State University San Luis Obispo, San Luis Obispo, California, USA
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3
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Thometz NM, Rosen DAS, Hermann-Sorensen H, Meranda M, Pardini M, Reichmuth C. Maintaining control: metabolism of molting Arctic seals in water and when hauled out. J Exp Biol 2023; 226:286206. [PMID: 36576033 DOI: 10.1242/jeb.244862] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [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: 08/07/2022] [Accepted: 12/12/2022] [Indexed: 12/29/2022]
Abstract
Seals haul out of water for extended periods during the annual molt, when they shed and regrow their pelage. This behavior is believed to limit heat loss to the environment given increased peripheral blood flow to support tissue regeneration. The degree to which time in water, particularly during the molt, may affect thermoregulatory costs is poorly understood. We measured the resting metabolism of three spotted seals (Phoca largha), one ringed seal (Pusa hispida) and one bearded seal (Erignathus barbatus) during and outside the molting period, while resting in water and when hauled out. Metabolic rates were elevated in spotted and ringed seals during molt, but comparable in water and air for individuals of all species, regardless of molt status. Our data indicate that elevated metabolism during molt primarily reflects the cost of tissue regeneration, while increased haul out behavior is driven by the need to maintain elevated skin temperatures to support tissue regeneration.
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Affiliation(s)
- Nicole M Thometz
- University of San Francisco, Department of Biology, 2130 Fulton Street, San Francisco, CA 94117, USA.,University of California Santa Cruz, Institute of Marine Sciences, 115 McAllister Way, Santa Cruz, CA 95060, USA
| | - David A S Rosen
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Holly Hermann-Sorensen
- University of California Santa Cruz, Department of Ocean Sciences, Santa Cruz, CA 95064, USA
| | - Madeline Meranda
- University of California Santa Cruz, Department of Ocean Sciences, Santa Cruz, CA 95064, USA
| | - Madilyn Pardini
- University of California Santa Cruz, Institute of Marine Sciences, 115 McAllister Way, Santa Cruz, CA 95060, USA
| | - Colleen Reichmuth
- University of California Santa Cruz, Institute of Marine Sciences, 115 McAllister Way, Santa Cruz, CA 95060, USA.,Alaska SeaLife Center, 301 Railway Avenue, Seward, AK 99664, USA
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John JS, Thometz NM, Boerner K, Denum L, Kendall TL, Richter BP, Gaspard JC, Williams TM. Metabolic trade-offs in tropical and subtropical marine mammals: unique maintenance and locomotion costs in West Indian manatees and Hawaiian monk seals. J Exp Biol 2021; 224:271210. [PMID: 34357378 PMCID: PMC8353161 DOI: 10.1242/jeb.237628] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 06/09/2021] [Indexed: 11/20/2022]
Abstract
Unlike the majority of marine mammal species, Hawaiian monk seals (Neomonachus schauinslandi) and West Indian manatees (Trichechus manatus latirostris) reside exclusively in tropical or subtropical waters. Although potentially providing an energetic benefit through reduced maintenance and thermal costs, little is known about the cascading effects that may alter energy expenditure during activity, dive responses and overall energy budgets for these warm-water species. To examine this, we used open-flow respirometry to measure the energy expended during resting and swimming in both species. We found that the average resting metabolic rates (RMRs) for both the adult monk seal (753.8±26.1 kJ h-1, mean±s.e.m.) and manatees (887.7±19.5 kJ h-1) were lower than predicted for cold-water marine mammal species of similar body mass. Despite these relatively low RMRs, both total cost per stroke and total cost of transport (COTTOT) during submerged swimming were similar to predictions for comparably sized marine mammals (adult monk seal: cost per stroke=5.0±0.2 J kg-1 stroke-1, COTTOT=1.7±0.1 J kg-1 m-1; manatees: cost per stroke=2.0±0.4 J kg-1 stroke-1, COTTOT=0.87±0.17 J kg-1 m-1). These lower maintenance costs result in less variability in adjustable metabolic costs that occur during submergence for warm-water species. However, these reduced maintenance costs do not appear to confer an advantage in overall energetic costs during activity, potentially limiting the capacity of warm-water species to respond to anthropogenic or environmental threats that require increased energy expenditure.
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Affiliation(s)
- Jason S John
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Nicole M Thometz
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA.,University of San Francisco, 2130 Fulton Street, San Francisco, CA 94117, USA
| | - Katharine Boerner
- Mote Marine Laboratory & Aquarium, 1600 Ken Thompson Pkwy, Sarasota, FL 34236, USA
| | - Laura Denum
- Mote Marine Laboratory & Aquarium, 1600 Ken Thompson Pkwy, Sarasota, FL 34236, USA
| | - Traci L Kendall
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Beau P Richter
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Joseph C Gaspard
- Pittsburgh Zoo & PPG Aquarium, One Wild Place, Pittsburgh, PA 15206, USA
| | - Terrie M Williams
- University of California Santa Cruz, Coastal Biology Building, 130 McAllister Way, Santa Cruz, CA 95060, USA
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Thometz NM, Hermann-Sorensen H, Russell B, Rosen DAS, Reichmuth C. Molting strategies of Arctic seals drive annual patterns in metabolism. Conserv Physiol 2021; 9:coaa112. [PMID: 33659059 PMCID: PMC7905162 DOI: 10.1093/conphys/coaa112] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/30/2020] [Accepted: 11/09/2020] [Indexed: 06/12/2023]
Abstract
Arctic seals, including spotted (Phoca largha), ringed (Pusa hispida) and bearded (Erignathus barbatus) seals, are directly affected by sea ice loss. These species use sea ice as a haul-out substrate for various critical functions, including their annual molt. Continued environmental warming will inevitably alter the routine behavior and overall energy budgets of Arctic seals, but it is difficult to quantify these impacts as their metabolic requirements are not well known-due in part to the difficulty of studying wild individuals. Thus, data pertaining to species-specific energy demands are urgently needed to better understand the physiological consequences of rapid environmental change. We used open-flow respirometry over a four-year period to track fine-scale, longitudinal changes in the resting metabolic rate (RMR) of four spotted seals, three ringed seals and one bearded seal trained to participate in research. Simultaneously, we collected complementary physiological and environmental data. Species-specific metabolic demands followed expected patterns based on body size, with the largest species, the bearded seal, exhibiting the highest absolute RMR (0.48 ± 0.04 L O2 min-1) and the lowest mass-specific RMR (4.10 ± 0.47 ml O2 min-1 kg-1), followed by spotted (absolute: 0.33 ± 0.07 L O2 min-1; mass-specific: 6.13 ± 0.73 ml O2 min-1 kg-1) and ringed (absolute: 0.20 ± 0.04 L O2 min-1; mass-specific: 7.01 ± 1.38 ml O2 min-1 kg-1) seals. Further, we observed clear and consistent annual patterns in RMR that related to the distinct molting strategies of each species. For species that molted over relatively short intervals-spotted (33 ± 4 days) and ringed (28 ± 6 days) seals-metabolic demands increased markedly in association with molt. In contrast, the bearded seal exhibited a prolonged molting strategy (119 ± 2 days), which appeared to limit the overall cost of molting as indicated by a relatively stable annual RMR. These findings highlight energetic trade-offs associated with different molting strategies and provide quantitative data that can be used to assess species-specific vulnerabilities to changing conditions.
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Affiliation(s)
- Nicole M Thometz
- Department of Biology, University of San Francisco, 2130 Fulton St, San Francisco, 94117 CA, USA
- Institute of Marine Sciences, University of California Santa Cruz, Long Marine Laboratory, 115 McAllister Way, Santa Cruz, 95060 CA, USA
| | - Holly Hermann-Sorensen
- Institute of Marine Sciences, University of California Santa Cruz, Long Marine Laboratory, 115 McAllister Way, Santa Cruz, 95060 CA, USA
| | - Brandon Russell
- Alaska SeaLife Center, 301 Railway Ave, Seward, 99664 AK, USA
| | - David A S Rosen
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, The University of British Columbia, 2202 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Colleen Reichmuth
- Institute of Marine Sciences, University of California Santa Cruz, Long Marine Laboratory, 115 McAllister Way, Santa Cruz, 95060 CA, USA
- Alaska SeaLife Center, 301 Railway Ave, Seward, 99664 AK, USA
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6
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Hermann-Sorensen H, Thometz NM, Woodie K, Dennison-Gibby S, Reichmuth C. In Vivo Measurements of Lung Volumes in Ringed Seals: Insights from Biomedical Imaging. J Exp Biol 2020:jeb.235507. [PMID: 34005800 DOI: 10.1242/jeb.235507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 08/17/2020] [Accepted: 12/11/2020] [Indexed: 11/20/2022]
Abstract
Marine mammals rely on oxygen stored in blood, muscle, and lungs to support breath-hold diving and foraging at sea. Here, we used biomedical imaging to examine lung oxygen stores and other key respiratory parameters in living ringed seals (Pusa hispida). Three-dimensional models created from computed tomography (CT) images were used to quantify total lung capacity (TLC), respiratory dead space, minimum air volume, and total body volume to improve assessments of lung oxygen storage capacity, scaling relationships, and buoyant force estimates. Results suggest that lung oxygen stores determined in vivo are smaller than those derived from postmortem measurements. We also demonstrate that-while established allometric relationships hold well for most pinnipeds-these relationships consistently overestimate TLC for the smallest phocid seal. Finally, measures of total body volume reveal differences in body density and net vertical forces in the water column that influence costs associated with diving and foraging in free-ranging seals.
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Affiliation(s)
- Holly Hermann-Sorensen
- University of California Santa Cruz. Department of Ocean Sciences, 115 McAllister Way, Santa Cruz CA 95060, USA
| | - Nicole M Thometz
- University of San Francisco, Department of Biology. 2130 Fulton Street, San Francisco, CA 94117, USA
- University of California Santa Cruz. Institute of Marine Sciences, 115 McAllister Way, Santa Cruz CA 95060, USA
| | - Kathleen Woodie
- Alaska SeaLife Center, 301 Railway Ave, Seward, AK 99664, USA
| | | | - Colleen Reichmuth
- Alaska SeaLife Center, 301 Railway Ave, Seward, AK 99664, USA
- University of California Santa Cruz. Institute of Marine Sciences, 115 McAllister Way, Santa Cruz CA 95060, USA
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7
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Abstract
Bearded (Erignathus barbatus), ringed (Pusa hispida), spotted (Phoca largha), and ribbon (Histriophoca fasciata) seals rely on seasonal sea-ice in Arctic and sub-Arctic regions. Many aspects of the biology and physiology of these seals are poorly known, and species-typical health parameters are not available for all species. Such information has proven difficult to obtain due to the challenges of studying Arctic seals in the wild and their minimal historic representation in aquaria. Here, we combine diagnostic information gathered between 2000 and 2017 from free-ranging seals, seals in short-term rehabilitation, and seals living in long-term human care to evaluate and compare key health parameters. For individuals in apparent good health, hematology, and blood chemistry values are reported by the source group for 10 bearded, 13 ringed, 73 spotted, and 81 ribbon seals from Alaskan waters. For a smaller set of individuals handled during veterinary or necropsy procedures, the presence of parasites and pathogens is described, as well as exposure to a variety of infectious diseases known to affect marine mammals and/or humans, with positive titers observed for Brucella, Leptospira, avian influenza, herpesvirus PhHV-1, and morbillivirus. These data provide initial baseline parameters for hematology, serum chemistries, and other species-level indicators of health that can be used to assess the condition of individual seals, inform monitoring and management efforts, and guide directed research efforts for Alaskan populations of ice-associated seals.
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Affiliation(s)
| | - Colleen Reichmuth
- Alaska SeaLife Center, Seward, AK, United States.,Institute of Marine Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Nicole M Thometz
- Institute of Marine Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States.,Department of Biology, University of San Francisco, San Francisco, CA, United States
| | - Heather Ziel
- Polar Ecosystems Program, Marine Mammal Laboratory, Alaska Fisheries Science Center, National Oceanic and Atmospheric Administration, Seattle, WA, United States
| | - Peter Boveng
- Polar Ecosystems Program, Marine Mammal Laboratory, Alaska Fisheries Science Center, National Oceanic and Atmospheric Administration, Seattle, WA, United States
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Thometz NM, Dearolf JL, Dunkin RC, Noren DP, Holt MM, Sims OC, Cathey BC, Williams TM. Comparative physiology of vocal musculature in two odontocetes, the bottlenose dolphin (Tursiops truncatus) and the harbor porpoise (Phocoena phocoena). J Comp Physiol B 2017; 188:177-193. [PMID: 28569355 DOI: 10.1007/s00360-017-1106-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 01/31/2017] [Accepted: 05/11/2017] [Indexed: 10/19/2022]
Abstract
The mechanism by which odontocetes produce sound is unique among mammals. To gain insight into the physiological properties that support sound production in toothed whales, we examined myoglobin content ([Mb]), non-bicarbonate buffering capacity (β), fiber-type profiles, and myosin heavy chain expression of vocal musculature in two odontocetes: the bottlenose dolphin (Tursiops truncatus; n = 4) and the harbor porpoise (Phocoena phocoena; n = 5). Both species use the same anatomical structures to produce sound, but differ markedly in their vocal repertoires. Tursiops produce both broadband clicks and tonal whistles, while Phocoena only produce higher frequency clicks. Specific muscles examined in this study included: (1) the nasal musculature around the phonic lips on the right (RNM) and left (LNM) sides of the head, (2) the palatopharyngeal sphincter (PPS), which surrounds the larynx and aids in pressurizing cranial air spaces, and (3) the genioglossus complex (GGC), a group of muscles positioned ventrally within the head. Overall, vocal muscles had significantly lower [Mb] and β than locomotor muscles from the same species. The PPS was predominately composed of small diameter slow-twitch fibers. Fiber-type and myosin heavy chain analyses revealed that the GGC was comprised largely of fast-twitch fibers (Tursiops: 88.6%, Phocoena: 79.7%) and had the highest β of all vocal muscles. Notably, there was a significant difference in [Mb] between the RNM and LNM in Tursiops, but not Phocoena. Our results reveal shared physiological characteristics of individual vocal muscles across species that enhance our understanding of key functional roles, as well as species-specific differences which appear to reflect differences in vocal capacities.
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Affiliation(s)
- Nicole M Thometz
- Department of Biology, University of San Francisco, 2130 Fulton St, San Francisco, CA, 94117, USA. .,Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California at Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA.
| | - Jennifer L Dearolf
- Biology Department, Hendrix College, 1600 Washington Ave., Conway, AR, 72032, USA
| | - Robin C Dunkin
- Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California at Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA
| | - Dawn P Noren
- Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, WA, 98112, USA
| | - Marla M Holt
- Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, WA, 98112, USA
| | - Olivia C Sims
- Biology Department, Hendrix College, 1600 Washington Ave., Conway, AR, 72032, USA
| | - Brandon C Cathey
- Biology Department, Hendrix College, 1600 Washington Ave., Conway, AR, 72032, USA
| | - Terrie M Williams
- Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California at Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA
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Thometz NM, Kendall TL, Richter BP, Williams TM. The high cost of reproduction in sea otters necessitates unique physiological adaptations. J Exp Biol 2016; 219:2260-4. [PMID: 27489214 DOI: 10.1242/jeb.138891] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [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: 02/17/2016] [Accepted: 05/16/2016] [Indexed: 11/20/2022]
Abstract
Superimposed on inherently high basal metabolic demands, the additional energetic requirements of reproduction can push female sea otters beyond physiological limits. Indeed, the resulting energy imbalance contributes to disproportionately high rates of mortality at the end of lactation in this species. To examine and quantify metabolic changes associated with reproduction, we measured the resting metabolic rate (RMR) of a female sea otter across gestation, lactation and non-reproductive periods. Concurrently, measurements were made on a non-breeding control female. Our results suggest that RMR declines during gestation. Conversely, RMR increases during lactation, reaches a peak at 3-4 months postpartum, and remains elevated until weaning. Combining these direct measurements with published data, we found the cost of pup rearing to be significantly higher than previously estimated. High baseline energy demands and limited energy reserves, combined with significant lactation and pup rearing costs, appear to necessitate metabolic and thermal lability during key reproductive stages.
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Affiliation(s)
- Nicole M Thometz
- Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California at Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060, USA
| | - Traci L Kendall
- Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California at Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060, USA
| | - Beau P Richter
- Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California at Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060, USA
| | - Terrie M Williams
- Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California at Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060, USA
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Thometz NM, Murray MJ, Williams TM. Ontogeny of Oxygen Storage Capacity and Diving Ability in the Southern Sea Otter (Enhydra lutris nereis): Costs and Benefits of Large Lungs. Physiol Biochem Zool 2015; 88:311-27. [DOI: 10.1086/681019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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