An endangered species of seal (Monachus schauinslandi) normally found on the leeward (southwest) sides of the Northwestern Hawaiian Islands, and occasionally sighted in the Main Hawaiian Islands. It is estimated that fewer than 1500 Hawaiian monk seals exist today. The Hawaiian monk seal was officially designated endangered 1976 and is protected by the Endangered Species Act and the Marine Mammal Protection Act. It is illegal to kill, capture or harass monk seals. A critically endangered species of monk seal (Monachus monachus) is found in the Mediterranean Sea. The Caribbean monk seal (Monachus tropicalis) is thought to be extinct.