Noren Shawn R, Iverson Sara J, Boness Daryl J
Conservation and Research Center, National Zoological Park, Smithsonian Institution, Washington, DC 20008, USA.
Physiol Biochem Zool. 2005 Jul-Aug;78(4):482-90. doi: 10.1086/430228. Epub 2005 May 24.
To successfully transition from nursing to foraging, phocid seal pups must develop adequate diving physiology within the limited time between birth and their first independent foraging trip to sea. We studied the postpartum development of oxygen stores in gray seals (Halichoerus grypus, n=40) to better understand the ontogeny of diving capacity in phocids. Hemoglobin (Hb), hematocrit (Hct), blood volume (BV), and myoglobin (Mb) levels in newborn (3 d postpartum [DPP]) and newly weaned (17+/-0.4 DPP) pups were among the lowest measured across age classes. During the pups' terrestrial postweaning fast (PWF), Hb, Hct, mass-specific BV, and Mb increased by 28%, 21%, 13%, and 29%, respectively, resulting in a 35% increase in total body mass-specific oxygen stores and a 23% increase in calculated aerobic dive limit (CADL). Although Hb and Hct levels at the end of the PWF were nearly identical to those of yearlings, total body mass-specific oxygen stores and CADL of weaned pups departing for sea were only 66%-67% and 32%-62%, respectively, of those for yearlings and adult females. The PWF represents an integral component of the physiological development of diving capacity in phocids; however, newly independent phocids still appear to have limited diving capabilities at the onset of foraging.
为了成功地从哺乳过渡到觅食，港海豹幼崽必须在出生到首次独立出海觅食的有限时间内发育出足够的潜水生理机能。我们研究了灰海豹（Halichoerus grypus，n = 40）产后氧储备的发育情况，以更好地了解鳍脚类动物潜水能力的个体发生。新生幼崽（产后3天[DPP]）和刚断奶幼崽（17±0.4 DPP）的血红蛋白（Hb）、血细胞比容（Hct）、血容量（BV）和肌红蛋白（Mb）水平在各年龄组中是测得的最低水平之一。在幼崽陆地断奶后禁食期（PWF），Hb、Hct、单位体重BV和Mb分别增加了28%、21%、13%和29%，导致全身单位体重氧储备增加35%，计算出的有氧潜水极限（CADL）增加23%。尽管PWF结束时的Hb和Hct水平与一岁龄海豹几乎相同，但即将出海的断奶幼崽的全身单位体重氧储备和CADL分别仅为一岁龄海豹和成年雌性海豹的66%-67%和32%-62%。PWF是鳍脚类动物潜水能力生理发育的一个组成部分；然而，新独立的鳍脚类动物在开始觅食时潜水能力似乎仍然有限。
