Sometimes called "living fossils," Hawaiian monk seals haven't changed in 15 million years. Named for their solitary behavior and the folds of skin on their neck—which resemble a monk's hood—monk seals are one of the most endangered marine animals in U.S. waters.

Hawaiian monk seals grow to be seven-feet long and can weigh up to 600 pounds. Females tend to be larger than males. Monk seals are classified as true seals, as opposed to fur seals or sea lions, since they have no external ears and use their hind flippers for propulsion and front flippers as stabilizers.

Habitat & Range

Hawaiian monk seals live mainly in the remote northwestern Hawaiian Island chain, including six major breeding locations: Kure Atoll, Midway Atoll, Pearl and Hermes Reef, Lisianski Island, Laysan Island, and French Frigate Shoals. Small populations occur on other remote islands and on the main Hawaiian Islands.

Very little is known of monk seal habits and distribution in offshore waters. Monk seals have a very diverse diet of fish, octopus, squid, and lobster.

Threats to Hawaiian Monk Seals

In 1976, the Hawaiian monk seal was listed as endangered under the federal Endangered Species Act. Despite their relatively remote habitat, seal hunting in the 19th and early 20th centuries devastated the population. They also have a high sensitivity to human interactions, direct and indirect. U.S. military operations in the islands prior to the 1990's disturbed the seals and hampered their ability to reproduce.

Today, most of the islands inhabited by monk seals have been designated as state or federal government refuges, minimizing direct human disturbance. Due to ocean currents converging near the northwestern Hawaiian Islands, fishing debris from thousands of miles away is often deposited there, creating a significant threat to the monk seals' recovery. In the past 20 years, more than 200 monk seals have been observed entangled in fishing gear or other debris.

An executive order signed by President Clinton in 2000 designated the Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve, which will help to protect the monk seals' habitat.

Other anthropogenic threats faced by monk seals include ingestion of marine debris or toxins, and limited food availability in some areas.

Additional threats to monk seals include mobbing (aggressive behavior by males which can result in the injury or death of adult females and immature seals), shark predation, and slow reproductive rates.