Harbor seals show aggression by growling, snorting, and waving threateningly with a foreflipper. Another aggressive behavior is head-thrusting - sharp, rapid extension and retraction of the neck. Fighting is rare, except between competing males during the mating season.
Harbor seals haul out onto rocks and beaches but remain alert and
wary. They show distinct preferences for certain haul-out sites that
may change seasonally.