UW News

Zoe Rand


September 23, 2025

Longer body size means more female calves for baleen whale moms

Two whales, a mother and her calf, swim toward the surface of the ocean.

University of Washington researchers found, in historical whaling data, that longer baleen whale mothers were more likely to birth female calves than males. These results run contrary to a leading evolutionary theory that suggests that fit mothers will benefit more from male offspring.