Large and in charge: cortisol levels vary with sex, diet, and body mass in an Antarctic predator, the leopard seal
Evaluating physiological responses in the context of a species’ life history, demographics, and ecology is essential to understanding the health of individuals and populations. Here, we measured the main mammalian glucocorticoid, cortisol, in an elusive Antarctic apex predator, the leopard seal (Hyd...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2023-06-01
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| Series: | Frontiers in Marine Science |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2023.1179236/full |
| _version_ | 1827918131903856640 |
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| author | Emily S. Sperou Daniel E. Crocker Renato Borras-Chavez Renato Borras-Chavez Renato Borras-Chavez Daniel P. Costa Michael E. Goebel Michael E. Goebel Shane B. Kanatous Douglas J. Krause Stephen J. Trumble Sarah S. Kienle |
| author_facet | Emily S. Sperou Daniel E. Crocker Renato Borras-Chavez Renato Borras-Chavez Renato Borras-Chavez Daniel P. Costa Michael E. Goebel Michael E. Goebel Shane B. Kanatous Douglas J. Krause Stephen J. Trumble Sarah S. Kienle |
| author_sort | Emily S. Sperou |
| collection | DOAJ |
| description | Evaluating physiological responses in the context of a species’ life history, demographics, and ecology is essential to understanding the health of individuals and populations. Here, we measured the main mammalian glucocorticoid, cortisol, in an elusive Antarctic apex predator, the leopard seal (Hydrurga leptonyx). We also examined intraspecific variation in cortisol based on life history (sex), morphometrics (body mass, body condition), and ecological traits (δ15N, δ13C). To do this, blood samples, life history traits, and morphometric data were collected from 19 individual leopard seals off the Western Antarctic Peninsula. We found that adult leopard seals have remarkably high cortisol concentrations (100.35 ± 16.72 μg/dL), showing the highest circulating cortisol concentration ever reported for a pinniped: 147 μg/dL in an adult male. Leopard seal cortisol concentrations varied with sex, body mass, and diet. Large adult females had significantly lower cortisol (94.49 ± 10.12 μg/dL) than adult males (120.85 ± 6.20 μg/dL). Similarly, leopard seals with higher isotope values (i.e., adult females, δ15N: 11.35 ± 0.69‰) had lower cortisol concentrations than seals with lower isotope values (i.e., adult males, δ15N: 10.14 ± 1.65‰). Furthermore, we compared cortisol concentrations across 26 closely related Arctoid taxa (i.e., mustelids, bears, and pinnipeds) with comparable data. Leopard seals had the highest mean cortisol concentrations that were 1.25 to 50 times higher than other Arctoids. More broadly, Antarctic ice seals (Lobodontini: leopard seal, Ross seal, Weddell seal, crabeater seal) had higher cortisol concentrations compared to other pinnipeds and Arctoid species. Therefore, high cortisol is a characteristic of all lobodontines and may be a specialized adaptation within this Antarctic-dwelling clade. Together, our results highlight exceptionally high cortisol concentrations in leopard seals (and across lobodontines) and reveal high variability in cortisol concentrations among individuals from a single location. This information provides the context for understanding how leopard seal physiology changes with life history, ecology, and morphology and sets the foundation for assessing their physiology in the context of a rapidly changing Antarctic environment. |
| first_indexed | 2024-03-13T03:38:25Z |
| format | Article |
| id | doaj.art-6106d1b70e06417d945f5eb3f74eeef6 |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-03-13T03:38:25Z |
| publishDate | 2023-06-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-6106d1b70e06417d945f5eb3f74eeef62023-06-23T12:19:05ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452023-06-011010.3389/fmars.2023.11792361179236Large and in charge: cortisol levels vary with sex, diet, and body mass in an Antarctic predator, the leopard sealEmily S. Sperou0Daniel E. Crocker1Renato Borras-Chavez2Renato Borras-Chavez3Renato Borras-Chavez4Daniel P. Costa5Michael E. Goebel6Michael E. Goebel7Shane B. Kanatous8Douglas J. Krause9Stephen J. Trumble10Sarah S. Kienle11Department of Biology, Baylor University, Waco, TX, United StatesDepartment of Biology, Sonoma State University, Rohnert Park, CA, United StatesDepartment of Biology, Baylor University, Waco, TX, United StatesCenter of Applied Ecology and Sustainability (CAPES), Department of Ecology, Pontificia Universidad Católica de Chile, Santiago, ChileDepartment of Projects, Instituto Antártico Chileno (INACH), Punta Arenas, ChileDepartment of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA, United StatesDepartment of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA, United StatesAntarctic Ecosystem Research Division, Southwest Fisheries Science Center, National Oceanic and Atmospheric Administration (NOAA) Fisheries, La Jolla, CA, United StatesDepartment of Biology, Colorado State University, Fort Collins, CO, United StatesAntarctic Ecosystem Research Division, Southwest Fisheries Science Center, National Oceanic and Atmospheric Administration (NOAA) Fisheries, La Jolla, CA, United StatesDepartment of Biology, Baylor University, Waco, TX, United StatesDepartment of Biology, Baylor University, Waco, TX, United StatesEvaluating physiological responses in the context of a species’ life history, demographics, and ecology is essential to understanding the health of individuals and populations. Here, we measured the main mammalian glucocorticoid, cortisol, in an elusive Antarctic apex predator, the leopard seal (Hydrurga leptonyx). We also examined intraspecific variation in cortisol based on life history (sex), morphometrics (body mass, body condition), and ecological traits (δ15N, δ13C). To do this, blood samples, life history traits, and morphometric data were collected from 19 individual leopard seals off the Western Antarctic Peninsula. We found that adult leopard seals have remarkably high cortisol concentrations (100.35 ± 16.72 μg/dL), showing the highest circulating cortisol concentration ever reported for a pinniped: 147 μg/dL in an adult male. Leopard seal cortisol concentrations varied with sex, body mass, and diet. Large adult females had significantly lower cortisol (94.49 ± 10.12 μg/dL) than adult males (120.85 ± 6.20 μg/dL). Similarly, leopard seals with higher isotope values (i.e., adult females, δ15N: 11.35 ± 0.69‰) had lower cortisol concentrations than seals with lower isotope values (i.e., adult males, δ15N: 10.14 ± 1.65‰). Furthermore, we compared cortisol concentrations across 26 closely related Arctoid taxa (i.e., mustelids, bears, and pinnipeds) with comparable data. Leopard seals had the highest mean cortisol concentrations that were 1.25 to 50 times higher than other Arctoids. More broadly, Antarctic ice seals (Lobodontini: leopard seal, Ross seal, Weddell seal, crabeater seal) had higher cortisol concentrations compared to other pinnipeds and Arctoid species. Therefore, high cortisol is a characteristic of all lobodontines and may be a specialized adaptation within this Antarctic-dwelling clade. Together, our results highlight exceptionally high cortisol concentrations in leopard seals (and across lobodontines) and reveal high variability in cortisol concentrations among individuals from a single location. This information provides the context for understanding how leopard seal physiology changes with life history, ecology, and morphology and sets the foundation for assessing their physiology in the context of a rapidly changing Antarctic environment.https://www.frontiersin.org/articles/10.3389/fmars.2023.1179236/fullleopard sealmarine mammalsintraspecific variationpinnipedcortisolphysiology |
| spellingShingle | Emily S. Sperou Daniel E. Crocker Renato Borras-Chavez Renato Borras-Chavez Renato Borras-Chavez Daniel P. Costa Michael E. Goebel Michael E. Goebel Shane B. Kanatous Douglas J. Krause Stephen J. Trumble Sarah S. Kienle Large and in charge: cortisol levels vary with sex, diet, and body mass in an Antarctic predator, the leopard seal Frontiers in Marine Science leopard seal marine mammals intraspecific variation pinniped cortisol physiology |
| title | Large and in charge: cortisol levels vary with sex, diet, and body mass in an Antarctic predator, the leopard seal |
| title_full | Large and in charge: cortisol levels vary with sex, diet, and body mass in an Antarctic predator, the leopard seal |
| title_fullStr | Large and in charge: cortisol levels vary with sex, diet, and body mass in an Antarctic predator, the leopard seal |
| title_full_unstemmed | Large and in charge: cortisol levels vary with sex, diet, and body mass in an Antarctic predator, the leopard seal |
| title_short | Large and in charge: cortisol levels vary with sex, diet, and body mass in an Antarctic predator, the leopard seal |
| title_sort | large and in charge cortisol levels vary with sex diet and body mass in an antarctic predator the leopard seal |
| topic | leopard seal marine mammals intraspecific variation pinniped cortisol physiology |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2023.1179236/full |
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