Reductions in the dietary niche of southern sea otters () from the Holocene to the Anthropocene.

The sea otter () is a marine mammal hunted to near extinction during the 1800s. Despite their well-known modern importance as a keystone species, we know little about historical sea otter ecology. Here, we characterize the ecological niche of ancient southern sea otters () using δC analysis and δN analysis of bones recovered from archaeological sites spanning ~7,000 to 350 years before present ( = 112 individuals) at five regions along the coast of California.