Rapado-Tamarit Beatriz, Méndez-Aróstegui Margarita, de Reus Koen, Sarraude Tom, Pen Ido, Groothuis Ton G G
Behavioural Biology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9700 CC Groningen, The Netherlands.
Sealcentre Pieterburen, Hoofdstraat 94A, 9968 AG Pieterburen, The Netherlands.
J Mammal. 2024 Dec 10;106(2):492-505. doi: 10.1093/jmammal/gyae128. eCollection 2025 Apr.
To study patterns in behavior, fitness, and population dynamics, estimating the age of the individuals is often a necessity. Specifically, age estimation of young animals is very important for animal rehabilitation centers because it may determine if the animal should be taken in and, if so, what care is optimal for its rehabilitation. Accurate age estimation is also important to determine the growth pattern of an individual, and it is needed to correctly interpret the influence of early body condition on its growth trajectories. The purpose of our study was to find body measurements that function as good age estimators in young (up to 3 months old) harbor seals (), placing emphasis on noninvasive techniques that can be used in the field. To meet this goal, body mass (BM), dorsal standard length (DSL), upper canine length (CL), body condition (BC), and sex were determined from 45 Harbor Seal pups of known age. Generalized additive mixed models were fitted to find how well these morphometric measures predicted age, and the results from the selected model were used to compute growth curves and to create a practical table to determine the age of young animals in the field. We found that both DSL and CL-and to some extent sex-were useful predictors for estimating age in young harbor seals and that the growth rate of pups raised in captivity is significantly lower than for those raised in the wild. In addition, we found no evidence for compensatory growth, given that animals that arrived at the center with a poor BM or BC continued to show lower BM or BC throughout almost the entire rehabilitation period.
为了研究行为、健康状况和种群动态模式，估算个体年龄往往是必要的。具体而言，对于动物康复中心来说，幼龄动物的年龄估算非常重要，因为这可能决定是否收留该动物，以及如果收留的话，何种护理方式对其康复最为适宜。准确的年龄估算对于确定个体的生长模式也很重要，并且对于正确解读早期身体状况对其生长轨迹的影响也是必需的。我们研究的目的是找到可作为幼龄（3个月龄及以下）斑海豹良好年龄估算指标的身体测量指标，重点关注可在野外使用的非侵入性技术。为实现这一目标，我们测定了45只已知年龄的斑海豹幼崽的体重（BM）、背侧标准长度（DSL）、上犬齿长度（CL）、身体状况（BC）和性别。拟合广义相加混合模型以确定这些形态测量指标对年龄的预测效果，并利用所选模型的结果计算生长曲线，创建一个实用表格以确定野外幼龄动物的年龄。我们发现，DSL和CL以及在一定程度上性别，都是估算幼龄斑海豹年龄的有用预测指标，并且圈养幼崽的生长速率显著低于野生幼崽。此外，我们没有发现补偿性生长的证据，因为那些进入中心时体重或身体状况较差的动物在几乎整个康复期内体重或身体状况持续较低。
