TY - JOUR
T1 - Juvenile southern elephant seals exhibit seasonal differences in energetic requirements and use of lipids and protein stores
AU - Field, Iain C.
AU - Bradshaw, Corey J A
AU - Burton, Harry R.
AU - Hindell, Mark A.
N1 - Copyright 2005 by University of Chicago Press. Originally published in Physiological and biochemical zoology.
PY - 2005/7
Y1 - 2005/7
N2 - Growing juvenile animals undergo many morphological, physiological, and behavioural changes that influence their energetic requirements, patterns of energy use, and ultimately, their survival and reproductive success. We examined changes in mass loss and body composition of juvenile southern elephant seals (1- and 2-yr-olds) during their two annual haul-outs. At the start and end of the midyear and molt haul-outs, we caught, weighed, and measured 41 and 14 seals, respectively. We measured blubber depth using ultrasound to estimate body composition (lean and adipose tissue mass). Using energy densities of the adipose and lean tissue, we calculated total, lean, and adipose mass changes and energy expenditure. While molting, juvenile seals used more energy than during the midyear, which is related to the increased use of lean tissue for hair and skin regeneration. The amount of energy used increases with mass as individuals mature. We found sexual differences in energy use where females retained greater fat reserves than males by utilizing more lean tissue. These differences are most likely related to haul-out function and behavior, growth, and earlier development of females toward sexual maturity.
AB - Growing juvenile animals undergo many morphological, physiological, and behavioural changes that influence their energetic requirements, patterns of energy use, and ultimately, their survival and reproductive success. We examined changes in mass loss and body composition of juvenile southern elephant seals (1- and 2-yr-olds) during their two annual haul-outs. At the start and end of the midyear and molt haul-outs, we caught, weighed, and measured 41 and 14 seals, respectively. We measured blubber depth using ultrasound to estimate body composition (lean and adipose tissue mass). Using energy densities of the adipose and lean tissue, we calculated total, lean, and adipose mass changes and energy expenditure. While molting, juvenile seals used more energy than during the midyear, which is related to the increased use of lean tissue for hair and skin regeneration. The amount of energy used increases with mass as individuals mature. We found sexual differences in energy use where females retained greater fat reserves than males by utilizing more lean tissue. These differences are most likely related to haul-out function and behavior, growth, and earlier development of females toward sexual maturity.
UR - http://www.scopus.com/inward/record.url?scp=21044453652&partnerID=8YFLogxK
U2 - 10.1086/430227
DO - 10.1086/430227
M3 - Article
C2 - 15957104
AN - SCOPUS:21044453652
SN - 1522-2152
VL - 78
SP - 491
EP - 504
JO - Physiological and Biochemical Zoology
JF - Physiological and Biochemical Zoology
IS - 4
ER -