Killing the protected animals may be the only way to stop them from eating too many of the Pacific Northwest’s endangered salmon.

To rule out nutrient scarcity as a cause, he says you’d need to look not only at the quantity of food, but also the quality. For example, he says steller sea lions have experienced population declines ...

Animals that researchers call “supersucklers” come back to nurse even after they can hunt, mate and fend for themselves.