The development of diving behavior in juvenile Weddell seals: pushing physiological limits in order to survive
The development of diving behavior in juvenile Weddell seals: pushing physiological limits in order to survive
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DOI：
10.1139/cjz-77-5-737
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发表时间：
1999-05-01
期刊：
影响因子：
--
通讯作者：
Burns, JM
中科院分区：
文献类型：
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作者：
Burns, JM
在少年phocids，从护理到独立觅食的成功过渡取决于在断奶和身体储备耗尽之间的有限时间内发展足够的潜水技能。然而，由于幼年海豹的体型较小，代谢率较高，氧气储存量较低，它们无法像成年海豹那样长时间地保持在水下，因此它们的行为选择可能受到限制。为了确定这种限制可能会影响觅食策略，我们研究了潜水行为和生理学的发展威德尔海豹（Leptonychotes weddellii）青少年，结合使用时间深度记录仪，卫星连接的潜水记录仪，形态和生理测量（质量和血液化学）。时间深度记录仪数据表明，平均深度，持续时间和频率的潜水幼仔从出生到断奶期间迅速增加，但随后不久放缓。虽然断奶前增加这些参数与海豹年龄，断奶后增加潜水能力是渐进的，可能是由于质量和身体成分的变化较慢。在断奶幼犬和一岁鸽，潜水频率和石灰水下增加年龄和（或）质量。尽管它们的体型较小，绝对能量需求较低，但幼鱼在水中度过的时间与成年鱼相似。然而，由于青少年无法保持淹没，只要成年人，因为大多数觅食潜水深，青少年无法花同等数量的时间在觅食深度。这种差异是显而易见的，即使青少年潜水更接近他们的无氧阈值比成年人。这些研究结果支持的假设，年轻的海豹觅食效率降低相对于成年人，由于有氧潜水时间的生理和形态的限制，并表明，低少年的生存可能会导致行为的限制。
In juvenile phocids, the successful transition from nursing to independent foraging is contingent upon the development of adequate diving skills within the limited time between weaning and the depletion of body reserves. Yet, because juvenile seals are unable to remain submerged for as long as adults, owing to their smaller size, higher metabolic rates, and lowered oxygen stores, their behavioral options are likely constrained. To determine how such limitations might influence foraging strategies, we studied the development of diving behavior and physiology in Weddell seal (Leptonychotes weddellii) juveniles, using a combination of time-depth recorders, satellite-linked dive recorders, and morphological and physiological measurements (mass and blood chemistry). Time-depth recorder data indicated that the average depth, duration, and frequency of dives made by pups increased rapidly in the period from birth through weaning, but slowed soon thereafter. While preweaning increases in these parameters were correlated with seal age, postweaning increases in dive capacity were gradual and were probably the result of slower changes in mass and body composition. In weaned pups and yearlings, dive frequency and lime underwater increased with age and (or) mass. Despite their smaller size and lower absolute-energy requirements, the amount of time juveniles spent in the water was similar to that spent by adults. However, because juveniles were unable to remain submerged as long as adults and because most foraging dives were deep, juveniles were unable to spend an equivalent amount of time at the foraging depths. This difference was evident even though juveniles dove much closer to their anaerobic threshold than did adults. These findings support the hypothesis that the foraging efficiency of younger seals is reduced relative to that of adults, owing to physiological and morphological constraints on aerobic dive duration, and suggests that low juvenile survival might result from behavioral constraints.