02 August 2023: New paper “Prolonged baleen hormone cycles suggest atypical reproductive endocrinology of female bowhead whales”

The paper “Prolonged baleen hormone cycles suggest atypical reproductive endocrinology of female bowhead whales” by Nadine Lysiak (Suffolk University, USA) and co-authored by NAMMCO Scientific Committee member, Mads Peter Heide-Jørgensen (Greenland Institute of Natural Resources), was recently published in Royal Society Open Science.

In this study, researchers used serial measurements of hormone concentrations along baleen plates to investigate reproductive histories in bowhead whales (Balaena mysticetus), analysing gestation and calving intervals in ten female whales from the eastern Canada-west Greenland population.

Seven mature females from the study population displayed repeated and sustained elevations of progesterone, suggesting pregnancies, and the mean duration of progesterone elevations was found to be approximately 23.6 months. This is significantly longer than the previously estimated gestation period of around 14 months for bowhead whales.

The results obtained in this study suggest that female bowhead whales could halt pregnancies for up to nine months, potentially making them the mammals with the longest pregnancy duration. In addition, the novel reproductive knowledge obtained in this study certainly contributes to a better understanding of whale biology and will serve to improve conservation efforts.

You can read the study by Lysiak et al. (2023) here: https://doi.org/10.1098/rsos.230365

Learn more about bowhead whales here: https://nammco.no/bowhead-whale/