Monk seals are species belonging to the taxonomic genus Monachus. The Genus contains three species of monk seals: The Hawaiian Monk Seal (''M. schauinslandi''), Caribbean Monk Seal (''M. tropicalis''), and Mediterranean Monk Seal (''M. monachus''). These three different monk seals live in three different locations as their names imply. Their appearances, behavior, and prey are extremely similar between the three species and only their locations differ. Both the Hawaiian and Mediterranean Monk Seals are critically endangered with less than 2000 total individuals left! The Caribbean Monk Seal has already been considered extinct. Therefore the critically endangered species are protected by the government.
Monk seals have a torpedo shaped body which enables them to catch prey quickly, such as octopus. Monk seals are mostly gray with a white belly. Hawaiian Monk Seals specifically are unable to rotate their rear flippers underneath their body. Also they have ears that are external. Most male monk seals are smaller weighing about 300 - 400 pounds and 7 feet in length. Females on the other hand weigh about 400-600 pounds and are ~8 feet and length.
Mediterranean Monk seals have a very similar design to the other monk seals. Like Hawaiian monk seals they are ~8 feet in length, but a bit heavier ranging 530-880 pounds. Their body color ranges from brown to gray, unlike the Hawaiian Monk Seals who are just gray. Their belly color is lighter than their body color, but is not always white.  Male Caribbean monk seal are thought to have been about 6 - 8 feet long and weighing ~440 pounds, being slightly larger than females. 
Hawaiian Monk Seals' lifespan range 25 - 30 years. They mature at about 5 years old, but that is not known for sure about males. Baby monk seals, also known as pups, are carried in the womb for 10 - 11 months before being born. Hawaiian monk seals have been known to give birth year round, but it is most common in late March and early April. After being born the mother nurses the pup for approximately 1 month then leaves it. While mother monk seals are usually caring toward only their young there have been cases of mothers caring about others' young. Hawaiian monk seal pups are about 30 - 40 pounds and 40 inches in length when born. When the mother nurses her young she usually loses about 300 pounds while the pup weighs 150 - 200 pounds.
Mediterranean monk seals on the other hand have a wide maturing range from 2 - 6 years old. Their life span ranges 20 - 30 years long. Similarly to Hawaiian monk seals, Mediterranean monk seals are developed in the mother's womb for about a year. The pups weigh approximately 35 - 45 pounds and are 30 - 48 inches in length when born. Unlike the Hawaiian monk seal mothers, the Mediterranean monk seal mothers will nurse their young for 4 months and have even been known to stay with their young for up to 4 years. Since the Caribbean monk seals have been extinct for quite a while their life patterns are not well known, but it is thought that their pups were born in early December.
Since the Caribbean monk seals are extinct scientists are not sure exactly where they inhabited the Caribbean. They are suspected to have lived along the coast of Central America up to the United States. The Hawaiian monk seals inhabit the waters of the south side of the Hawaiian islands. They breed mostly on the Northwest Main Hawaiian Islands. Mediterranean monk seals are mostly found along the north of Africa and along the Mediterranean Sea. They are larger populations along some of north Africa and Greece.
Caribbean monk seals are suspected to have spent their time swimming and sleeping on beach, like all monk seals do. There are thought to have eaten lobsters, tentacles of octopus, and reef fish. Hawaiian Monk Seal often rest on the beaches of Hawaii, while protected from harassment by Federal law. Mediterranean Monk Seals are thought to be able to dive down 100 m (~330 ft.) even though they spend most of their time in shallow waters. Their diet consists of a wide variety of fish including eels, sardines, tuna, lobsters, flatfish, mullet, and octopus.
Caribbean monk seals are now considered extinct since the last spotting was in 1952. Since Christopher Columbus’s men began killing them for food, they were hunted for commercial sales. They were hunted for their meat, pelts, and oil until extinction. Mediterranean monk seals are extremely close to extinction with less than ~400 seals. With such a small population they are one of the rarest animals to find. Like Caribbean monk seals they have been hunted to almost extinction for their skin. One of the greatest reductions in their population was in 1997 when the population on the north African fell from 310 to less than 90.
The Hawaii monk seal population is at ~1,200 and it is decreasing every year. They are threatened by several things mostly caused by humans. One of the biggest killers are diseases passed on by humans. Because of their low genetic variability when disease attacks it causes a great reduction in numbers. Another is fragments such as garbage or fishing nets which trap the seal. The most obvious reason is the lack of food for monk seals in the northwest of the Hawaiian Islands. Some cases of extreme aggression by males that end up killing the female. As an effort to raise fund to save the Hawaiian monk seals the University of California created a seal plush toy for sale. Each seal contains information about one unique Hawaiian monk seal allowing only 1,100 to be made because of the small monk seal population.
- Monachus Wikispecies. Web. Last modified on 22 December 2012.
- Hawaiian Monk Seal Habitat & DietAnimals Time. Web. Last Accessed 4 April 2014. Author Unknown.
- Mediterranean Monk Seal (Monachus monachus)NOAA Fisheries Office of Protected Resources. Web. Last Accessed 6 April 2014. Author Unknown.
- Caribbean monk seal (M. tropicalis) The Society for Marine Mammalogy. Web. Last Accessed 23 March 2014. Kenady, Wilson.
- Hawaiian Monk Seal (Monachus schauinslandi)NOAA Fisheries Office of Protected Resources. Web. Last Updated 27 February 2013. Author Unknown.
- Mediterranean Monk Seals, Monachus monachusMarineBio. Web. Last Accessed 23 March 2014. Author Unknown.
- Hawaiian monk seal toy raises funds to save endangered speciesUNIVERSITY OF CALIFORNIA. Web. Created 9 December 2013. Stephens Tim.