Until recently, the Mediterranean monk seal Monachus monachus, the Hawaiian monk seal Neomonachus schauinslandi and the now extinct Caribbean monk seal Neomonachus tropicalis, were part of the Monachus genus, a group of seals the spread of which is located in sub-tropical and temperate regions of the planet. However, more recent scientific data regarding the genetic identification and the morphology of the species, have led to the distinction of this group, and as a result, the Mediterranean monk seal is today the only representative of the Monachus genus. The Mediterranean monk seal was first described by Aristotle, while in 1779 the first scientific documentation of the species was recorded by Jean Hermann. Hermann named the species Phoca monachus, due to the resemblance with the monks wearing hooded capes at the time, and not because of its lonely nature, which is commonly mentioned.

The Hawaiian Monk Seal

The Hawaiian monk seal (Neomonachus schauinslandi) lives in the islands of the Hawaiian Archipelago and the current population of the species is estimated to number approximately 1,100 individuals. With the total population of the species feared to drop below 1,000 individuals in the near future, the Hawaiian monk seal is one of the most endangered seals on earth. Adult Hawaiian monk seals are silver, grayish – brown, can reach up to a length of 2.3m and a weight of 170 – 205 kg and live up to 30 years. The species can spend up to a month at sea, dive to depths of 300 m and stay more than 20 minutes underwater. Hawaiian monk seals feed on fish, cephalopods and crustaceans and prefer prey that is easy to catch. Each year, usually between March and April, female Hawaiian monk seals come on land at sandy beaches, where they give birth to 1 pup, which they nurse for approximately 6 weeks. During this time the mothers do not leave the side of their newborn pups on the beach and fast while their pups are nursing.

The main threats to the survival of the Hawaiian monk seal are:

• Reduction of available food resources and interspecific competition with other top predators
• Drowning of young animals through entanglement in derelict fishing gear
• Intentional killing by humans
• Habitat degradation
• Predation by sharks, who are their main natural enemy and usually attack newborn pups and juveniles

The Caribbean Monk Seal

The Caribbean monk seal (Neomonachus tropicalis) became known to European explorers approximately 500 years ago when Christopher Columbus sighted the species off Cuba and named it the “Sea Wolf”. The species was a large seal, approximately 2.4 m long and 200 kg in weight, brown with a grey tinge on the dorsal side and pale-yellow on the ventral side. Caribbean monk seals lived primarily at sea and came on land at rocky and sandy shores to rest and give birth to their young. Their diet included fishes, Cephalopods and Crustaceans. 

The species was heavily exploited since its discovery, and as a result the population was dramatically reduced in the last centuries. Unfortunately the species is now considered to be extinct, as the last sighting of a Caribbean monk seal in the wild dates back more than 50 years!