Mystery of Missing Blue Whale Calves Potentially Solved: Research Suggests Birth Timing and Location Key to Unseen Births

The elusive nature of blue whale births has long puzzled researchers. A new study from the University of Washington, published in *Endangered Species Research*, proposes that the timing and location of births are the primary reasons why they are rarely observed. Historically, only two blue whale births have been recorded. While blue whales migrate to colder regions like off California to feed during the summer, they return to warmer waters like the Gulf of California and the eastern tropical Pacific in the winter to give birth. Calves are weaned around seven months after birth, before the whales return to their summer feeding grounds. Professor Trevor Branch suggests that because most research occurs during the summer feeding season, the winter birthing season is largely unobserved. This timing hypothesis aligns with data showing higher calf proportions in winter regions and lower proportions in summer regions. The findings offer hope that increased monitoring in winter and spring could lead to more calf sightings, indicating a healthy population.