Paleosuchus palpebrosus is the smallest crocodilian alive. Adult males typically stop between 1.2 and 1.6 metres and females below 1.2, which is roughly a quarter of the length of a large saltwater crocodile.
Its defence is bone. Osteoderms are extensive on the dorsal surface and unusually well developed on the belly, and the species name palpebrosus refers to bony plates within the upper eyelid. This dense ossification means the skin cannot be tanned into supple leather, and the species was therefore largely spared the commercial hide hunting that devastated the black caiman. Instead the pressure has come from the pet trade and from habitat change.
The caiman occupies cool, fast, often nutrient-poor forest streams and rocky watercourses, and shelters in burrows during the day. Because its habitat is hard to survey, population estimates are weak, and its Least Concern assessment rests more on wide distribution than on measured abundance.