[3] The last confirmed sighting of a Caribbean monk seal was in 1952, at Serranilla Bank, in the waters west of Jamaica and off the eastern coast of Nicaragua.

[6][7] Caribbean monk seals had a relatively large, long, robust body, could grow to nearly 2.4 metres (8 ft) in length and weighed 170 to 270 kilograms (375 to 600 lb).

[8] Historical records suggest that this species may have "hauled out" at resting areas on land in large social groups, typically 20–40 animals, but sometimes up to 100 individuals, throughout its range.

Newborn pups were probably about 1 metre (3 ft 3 in) in length and weighed 16 to 18 kilograms (35 to 40 lb) and reportedly had a sleek, black lanugo coat when born.

They probably preferred to haul out at low sandy beaches above high tide on isolated and secluded atolls and islands, but occasionally would visit the mainland coasts and deeper waters offshore.

In August 1494, a ship laid anchor off the mostly barren island of Alta Velo, south of Hispaniola, where the party of men aboard killed eight seals that were resting on the beach.

[10] The second recorded interaction with Caribbean monk seals was Juan Ponce de León's discovery of the Dry Tortugas Islands.

On June 21, 1513, when Ponce de León discovered the islands, he ordered a foraging party to go ashore, where the men killed fourteen of the docile seals.

[11] There are several more records throughout the colonial period of seals being discovered and hunted at Guadeloupe, the Alacrane Islands, Bahamas, Pedro Cays, and Cuba.

[21] The Caribbean monk seals' docile nature and lack of flight instinct in the presence of humans made them very easy to kill.

[22] Surprisingly few conservation measures were taken towards attempting to save the Caribbean monk seal; by the time it was placed on the endangered species list in 1967, it was likely already extinct.

[20] Unconfirmed sightings of Caribbean monk seals by local fishermen and divers are relatively common in Haiti and Jamaica, but two recent scientific expeditions failed to find any sign of the species.

It is possible the mammal is still extant, but some biologists strongly believe the sightings are of wandering hooded seals, which have been positively identified on Caribbean archipelagos such as Puerto Rico and the Virgin Islands.