Male Bowhead Whale Reproductive Histories Inferred from Baleen Testosterone and Stable Isotopes.

ABSTRACT: Male mammals of seasonally reproducing species typically have annual testosterone (T) cycles, with T usually peaking during the breeding season, but occurrence of such cycles in male mysticete whales has been difficult to confirm. Baleen, a keratinized filter-feeding apparatus of mysticetes, incorporates hormones as it grows, such that a single baleen plate can record years of endocrine history with sufficient temporal resolution to discern seasonal patterns. We analyzed patterns of T every 2 cm across the full length of baleen plates from nine male bowhead whales (Balaena mysticetus) to investigate occurrence and regularity of T cycles and potential inferences about timing of breeding season, sexual maturation, and reproductive senescence. Baleen specimens ranged from 181-330 cm in

SUBMITTER: Hunt KE 

PROVIDER: S-EPMC9125798 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature