Holothuria thomasi

Holothuria thomasi, called the tiger's tail, is a sea cucumber belonging to the family Holothuriidae. It holds the record as the largest sea cucumber in the western Atlantic, but its excellent camouflage meant scientists did not formally describe it until 1980. Its full scientific name is Holothuria (Thymiosycia) thomasi, placing it in the subgenus Thymiosycia.

This species gets its common name from its tiger-like appearance. Its body is a long, rounded cylinder with blunt ends, reaching up to 2 meters in length. The skin is mottled with dark brown, golden brown, and white patches and streaks, sometimes forming irregular rings. The upper side bears dark brown, thorn-like projections called papillae, each tipped with white.

The underside is lighter in color and has several lengthwise rows of tube feet. The animal lacks eyes; its mouth sits at the front end, ringed by about twenty shield-shaped tentacles. When feeding, this front end expands. Small individuals move around freely, but larger ones hide in crevices or under overhangs and are rarely seen.

The tiger's tail lives in the Caribbean Sea, the Gulf of Mexico, and nearby waters. It inhabits coral reefs, concealed among the bases of corals at depths between 3 and 30 meters. Its preferred spot is the outer reef's escarpments, between the outer ridge and the steep reef slopes.

As a scavenger, it anchors its rear end firmly in a crack or under a rock. It then sweeps the front third of its body over the surrounding sand and algae-covered rocks. Its tentacles grab detritus, sand, gravel, and algae, pushing them into its mouth. The material passes through its gut, and the animal expels the indigestible fragments through its anus.