Le jacara est un prédateur carnivore dont le régime alimentaire se compose essentiellement d'invertébrés aquatiques tels que les escargots et de vertébrés comme les poissons et occasionnellement les serpents.

As a medium to small to mid-sized crocodilian, most adult males grow to roughly 2 or 2.5 m (6.6 or 8.2 ft) in length, with the occasional 3 m (9.8 ft) individual (reports of 4 m (13 ft) individuals within the pantanal are yet to be verified). Females are rather smaller at an average of 1.4 m (4.6 ft). Body mass in this species can range up to 58 kg (128 lb) in males and from 14 to 23 kg (31 to 51 lb) in females. Their relatively smaller size makes a small sized individual makes a potential prey of the jaguar and anaconda. This species' diet consists primarily of fish (especially piranha) and birds,retiles,small mammals. with the occasional large mammals (especially capybara) being taken by larger adults. In general, due to their size, this species is not considered to be fatally dangerous to humans.