For orca moms, raising sons has a heavy cost

Orca whales are among the world’s most recognizable whales, with their round Oreo-cookie colored bodies, acrobatics, and apex ocean predator status. Many populations of orcas–aka killer whales–are also in trouble, and not just due to decades of captivity.

The unique and endangered Southern Resident killer whales (SRKW) that live off of the northwest coast of North America specialize in eating Chinook salmon, a particularly large, fatty, and nutritious Pacific salmon. The whales have become endangered for multiple reasons including reduced salmon availability, chemical…