Hearing and sight are highly developed in harbour seals. The harbour seal may use echolocation. The harbour seal's sense of smell can be used to locate a lost pup. Steller sea lions are larger and have longer flippers. They are very vocal, territorial and aggressive.
Sea lions are also able to support themselves on their front two flippers and walk.
Seals have smaller and sleeker torpedo shaped bodies. They rarely vocalize and are quite shy. Seals do not use their flippers to support their bodies and move by sliding or shuffling. When the seal's face is submerged, it automatically holds its breath, its heartbeat slows by up to 90 percent and its blood circulation is reduced, except to the most vital organs, the heart and brain. A harbour seal is capable of maximum dive depths approaching 300 metres and for durations of nearly 25 minutes in adults.