Mainly solitary in water, forms usually small groups when ashore or out of water on exposed rocks (sometimes up to several hundred). Mean maximum distance between haulout sites used by adults in Alaska was 14.7 kilometers; at-sea foraging area size averaged 267 square kilometers for adults and 385 square kilometers for subadults (Small and ver Hoef 2001).

Common causes of mortality include abandonment or orphaning of pups and predation by sharks, killer whales, and sometimes other mammals. Also, outbreaks of disease (influenza, distemper) sometimes kill hundreds or thousands of individuals in a local or regional population.