Ageing gracefully: physiology but not behaviour declines with age in a diving seabird

• Published in: Functional Ecology
• Main Authors: H. Elliott, Kyle, F. Hare, James, Le Vaillant, Maryline, J. Gaston, Anthony, Ropert‐Coudert, Yan, Gary Anderson, W.
• Other Authors: Department of Biological Sciences Winnipeg, University of Manitoba Winnipeg, Département Ecologie, Physiologie et Ethologie (DEPE-IPHC), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), National Wildlife Research Center, Environment and Climate Change Canada, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: [SDE]Environmental Sciences; [SDV]Life Sciences [q-bio]; Uria lomvia; uria
• Online Access: https://hal.archives-ouvertes.fr/hal-01037965; https://doi.org/10.1111/1365-2435.12316

International audience Summary 1. A higher proportion of long-lived animals die from senescence than short-lived animals, yet many long-lived homeotherms show few signs of physiological aging in the wild. This may, however, differ in long-lived diving homeotherms that frequently encounter hypoxic conditions and have very high metabolic rates. 2. To examine aging within a long-lived diving homeotherm, we studied resting metabolism and thyroid hormones (N = 43), blood oxygen stores (N = 93), and foraging behaviour (N = 230) of thick-billed murres (Uria lomvia). Because murres dive exceptionally deep for their size and have a very high metabolism, we expected that aging murres would show signs of physiological senescence. We paid particular attention to resting metabolism as we argue that these maintenance costs reflect those experienced during deep dives. 3. Blood oxygen stores (hematocrit), resting metabolic rate and thyroid hormone levels all declined significantly with age in incubating murres 3-30 years of age. In birds measured longitudinally three years apart, thyroid hormone levels and hematocrit were both significantly lower, suggesting progressive changes within individuals rather than selective disappearance of individuals with high metabolic rates. Within our longitudinal dataset, we found no effect of age on dive depth, dive shape, or behavioural aerobic dive limit. 4. A meta-analysis of changes in resting metabolism with age across 15 animal species demonstrated that such declines are pervasive across most of the kingdom. The rate of decline was highest in species with high energy expenditure supporting a linkage between metabolism and senescence. 5. Physiological changes occurred in tandem with advancing age in murres, but offset each other such that there was no detectable decline in behavioural performance.