The fat and the furriest: morphological changes in harp seal fur with ontogeny.

摘要: Ontogenetic changes in physiological performance often exemplify the development of adaptations to environmental challenges. For mammals polar regions, extreme cold environment presents a constant challenge thermal homeostasis. The harp seal (Pagophilus groenlandicus) is an Arctic species that shifts its thermoregulatory strategy with ontogeny. Adult seals primarily use blubber for insulation, but newborn instead rely on their fur coat while layer develops. Harp pups are weaned abruptly, less than 2 wk after birth, and must subsequently learn swim dive frigid waters own. This study examined how morphological characteristics change We compared hair length, circularity, density neonates (1 d old; n = 7), early-nursing (4 3), late-nursing (9 4), newly (molting) (2 5), late-weaned (molted) (3 adult (n 4). Hairs were shorter (P < 0.001) flatter older animals. Additionally, decreased age 0.001), terms both average number bundles per unit area underhairs present any given bundle. These associated reduced resistance pelt adults 0.001). Results consistent known evolutionary patterns morphology transition from aquatic species, yet this first time such differences have been demonstrated across classes within single species. Thus, ontogenetic described here recapitulate convergent phylogenetic observed secondarily Overall, timing these may limit ability adapt deterioration sea ice Arctic, as predicted continued climate change.