Northern elephant seal
Male northern elephant seals are the second largest of all the pinnipeds (after the southern elephant seal). They were once at risk of becoming extinct, but happily their numbers are now much healthier.
Males (bulls): 4.5m, 2500kg, Females (cows): 3.6m, 900 kg.
Male and female elephant seals are easily differentiated from each other, as males are much larger than females, are darker in colour and have an inflatable proboscis.
Both sexes are thickly insulated with blubber and males have thickened, wrinkled skin on their chests to protect them from the rigours of fighting for females.
Northern elephant seals are restricted to the north east Pacific Ocean. They dive repeatedly for food so sightings of them in the sea are relatively rare.
Elephants seals make deep dives in search of their prey, which includes fish and squid.
Occasionally, elephant seals are killed by great white sharks and killer whales.
The females congregate on sand and gravel beaches and give birth to one pup in the winter. During the breeding season, males show aggression to one another and will fight for access to females.
The males are polygamous (mate with more than one female) and dominate the females in their harem. Only the dominant males will gain access to the females and a third of the males will not breed at all in a season.
The northern elephant seal was driven to near extinction due to hunting in the late 1800s. Nowadays, numbers are estimated to be at a healthier 60,000 individuals.