Main Characteristics

Hawaiian Monk Seals are endangered marine mammals. They have a body length up to 2.4 m (8 ft) and they weigh between 136 and 272 kgs (300 - 600 lbs). They are grey in colour but turn brown with weathering.

They have streamline bodies, large hind flippers and smaller front flippers. They are excellent swimmers and use their hind flippers to propel themselves along and their front flippers act as rudders.

They can dive to depths of 500 m (1,640 ft) for as long as 20 minutes and they rest in a shaded area during the heat of the day and feed at night.

Habitat

Hawaiian Monk Seals are found on the small uninhabited north western Hawaiian Islands. They are seen around Ni'ihau, Kaua'i and French Frigate Shoals.

They are solitary and they spend their time at sea feeding or basking on a remote beach.

Diet

Hawaiian Monk Seals mainly feed on spiny lobster, eels, larval fish, flat fish, small reef fish and octopus.

They can spend many days at sea feeding, sometimes up to 1 month, and they can eat as much as 10% of their body weight in one day.

Breeding

During the breeding season male Hawaiian Monk Seals become aggressive and they will attack females. This form of attack is known as mobbing and often the female ends up badly injured or sometimes killed.

During May or June and after a gestation period of 335 days, 1 pup is born on a remote sandy beach. At birth the pups weigh between 13 and 18 kgs (30 - 40 lbs), they are approximately 1m (3.3 ft) in length and they are black in colour with short, fuzzy hair.

The female feeds the pup with fat rich milk for 6 weeks and during this time she doesn't leave the beach, she survives on the fat reserves she built up prior to giving birth. The pup rapidly grows during this period and can reach between 68 and 90 kgs (150 - 200 lbs) in weight.

When the pup reaches 3 - 5 weeks old it moults and it becomes grey/silver in colour on it dorsal surface and white in colour on its underside. The pup is weaned at 6 weeks and it learns to catch food for itself. During this period it can loose a large amount of weight but it soon regains it when it has mastered its hunting skills.

Compared to other seals and sea lions, Hawaiian Monk Seals have a high pup and juvenile survival rate. They reach sexual maturity when they are 5 years of age.

Predators

The main predators of Hawaiian Monk Seals are sharks.

Subspecies

Hawaiian Monk Seals have no subspecies

Interesting Facts

Hawaiian Monk Seals are endangered and there are only approximately 1,200 individuals left.

Ilio-holo-i-ka-uaua was the name given to the Hawaiian Monk Seal by the indigenous people of Hawaii and it means "dog that runs in rough waters"

It is believed that Hawaiian Monk Seals were given their common name because;
of their monk-like preference for solitude
or
their rounded head covered in short hairs giving it a monk-like appearance
or
perhaps because of the folds of skin around their neck resembles the hood of a monks robe.

Dr H Schauinsland obtained the first Hawaiian Monk Seal skull known to science hence the name "Monachus schauinslandi"

Hawaiian Monk Seals are very sensitive to disturbance by humans and they are protected by the Endangered Species Act and the Marine Mammal Protection Act.

Similar Animals

Caribbean Monk Seal
Mediterranean Monk Seal