GRAY SEAL, HALICHOERUS-GRYPUS, ENERGETICS - FEMALES INVEST MORE IN MALE OFFSPRING
GRAY SEAL, HALICHOERUS-GRYPUS, ENERGETICS - FEMALES INVEST MORE IN MALE OFFSPRING
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DOI：
10.1111/j.1469-7998.1987.tb04478.x
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发表时间：
1987-04-01
影响因子：
2
通讯作者：
FEDAK, MA
中科院分区：
文献类型：
--
作者：
ANDERSON, SS;FEDAK, MA
在短暂的哺乳期，雌性灰海豹将大量的能量传递给它们的幼崽。哺乳期的成本已经通过母亲和幼犬的体重变化来衡量。大的雌性在这个季节更早地上岸分娩，体重比小的雌性下降得更快。灰海豹幼仔角的性比在繁殖季节的早期偏向雄性。雄性幼崽出生时比雌性幼崽大，体重增加得更快，它们的母亲体重减轻的速度也相应地比雌性幼崽的母亲快。灰海豹母亲妊娠和哺乳的能量消耗为雄性幼崽3.1 GJ，雌性幼崽2.8 GJ。因此，从能量角度来看，雄性在断奶前的能量消耗要高出10%。因为，平均而言，大型雌性动物在较小的动物之前到达繁殖地点，所以从不使用重复称重的方法中会获得关于体重变化的偏倚结果。我们认为，高效率的哺乳期估计竖琴密封相比，其他phocid密封可以解释这样的偏见。
Grey seal females tranfer large amounts of energy to their pups during the brief lactation period. The costs of lactation have been measured using weight changes of mother and pup pairs. Large females come ashore to give birth earlier in the season and lose weight more rapidly than smaller females. The sex ratio of Grey seal pups horn is skewed towards males in the early part of the breeding season. Male pups are larger at birth and gain weight more rapidly than female pups, and their mothers show a correspondingly faster rate of weight loss than mothers of female pups. The energy costs of gestation and lactation to a Grey seal mother are 3.1 GJ for male pups and 2.8 GJ for female pups. males are therefore 10% more costly in energy terms to raise to weaning. Because, on average, large females arrive at breeding sites before smaller animals, biased results on weight changes would be obtained from methods which do not use repeated weighings. We suggest that the high efficiencies of lactation estimated for Harp seals compared with other phocid seals could be accounted for by such a bias.