Crocodylus rhombifer occupies one of the smallest natural ranges of any crocodilian. Fossil and subfossil remains show it formerly occurred across Cuba and on the Cayman Islands and Grand Bahama, but the wild population is now confined to Zapata Swamp in Matanzas province, with a small introduced or relict group in the Lanier Swamp.
It is built differently from other crocodiles. The legs are long and the hind feet only partly webbed, and the animal is notably capable on land. Its diet includes turtles and fish, and its teeth are robust enough for hard-shelled prey.
The most immediate genetic threat is hybridisation. American crocodiles occur in the same swamp, the two species interbreed, and genetic surveys have found hybrid animals both in the wild population and within captive breeding stock intended for release. How many apparently pure Cuban crocodiles remain, and how introgression should be managed, is actively contested among researchers.