Elephant Seal - Physiology

Physiology

Elephant seals spend upwards of 80% of their lives in the ocean. They can hold their breath for more than 100 minutes — longer than any other noncetacean mammal. Elephant seals dive to 1550 m beneath the ocean's surface (the deepest recorded dive of an elephant seal is 2,388 metres (7,835 ft) by a southern elephant seal). The average depth of their dives is about 300 to 600 metres (2,000 ft), typically for around 20 minutes for females and 60 minutes for males, as they search for their favorite foods, which are skates, rays, squid, octopuses, eels, small sharks, and large fish. Their stomachs also often contain gastroliths. While excellent swimmers, they are also capable of rapid movement on land.

Elephant seals are shielded from extreme cold by their blubber, more so than by fur. The animals' hair and outer layers of skin molt in large patches. The skin has to be regrown by blood vessels reaching through the blubber. When molting occurs, the seal is susceptible to the cold, and must rest on land, in a safe place called a "haul out". Northern males and young adults haul out during June to July to molt; northern females and immature seals during April to May.

Elephant seals have a very large volume of blood, allowing them to hold a large amount of oxygen for use when diving. They have large sinuses in their abdomens to hold blood and can also store oxygen in their muscles with increased myoglobin concentrations in muscle. In addition, they have a larger proportion of oxygen-carrying red blood cells. These adaptations allow elephant seals to dive to such depths and remain underwater for up to two hours.