[7][8] It was long confused with the American and Cuban crocodiles because of similar characteristics and an ambiguous type locality.

[10] Phylogenetic evidence supports Crocodylus diverging from its closest recent relative, the extinct Voay of Madagascar, around 25 million years ago, near the Oligocene/Miocene boundary.

[9] Below is a cladogram based on a 2018 tip dating study by Lee & Yates simultaneously using morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data,[11] as revised by the 2021 Hekkala et al. paleogenomics study using DNA extracted from the extinct Voay.

[13][15][16] One mature adult specimen measuring 2.84 m (9 ft 4 in) and weighing 110 kg (240 lb) had a bite force of 4,399 N (989 lbf).

[17] The weight of a large 3 m (10 ft) wild male crocodile is estimated to average around 150 kg (330+3⁄4 lb), although mass is likely much more in outsized individuals.

This species of crocodile can mainly be found in freshwater swamps and marshes which are located inland, and in large rivers and lakes.

[24] Juvenile crocodiles live in very dense cover to protect them from other predators that might be in the area and will remain there until they become older and able to fend for themselves.

[37][38] The sightings have prompted several municipal police departments to put up signs warning people about entering the river.

[40] Juvenile crocodiles feed largely on fish and insects until they become bigger and more capable of bringing down larger prey.

[23] Adults largely prey on small mammals, birds, other reptiles and fish, as well as gastropods, crustaceans and other invertebrates.

[16][40][41] Dogs and goats have been taken by this species, including a record of a 2.9 m (9 ft 6 in) adult killing an English sheepdog which weighed at least 35 kg (77 lb).

[44] Despite the relatively small size of the species, large adult Morelet's are capable of overpowering a human.

Predation of a Morelet’s crocodile by a jaguar was captured for the first time on a camera trap in the Calakmul Biosphere Reserve of Yucatán, Mexico in 2019.