Cuvier's Dwarf Caiman

Cuvier's dwarf caiman is the smallest living New World crocodilian. Males grow to a maximum length around 1.6 m (5.2 ft) while females do not usually exceed 1.2 m (3 ft 11 in). The largest specimen on record measured 1.73 m (5.7 ft) in length. This may be an underestimate of the animal's maximum size, as nearly all large adults have lost the tips of their tails and the largest specimen measured in the Pantanal region had a snout–vent length of 1.125 m (4 ft) (equivalent to a total length of 2.1 m (6.9 ft) with an intact tail). An adult typically weighs around 6 or 7 kg (13 or 15 lb), around the same weight as a 6- to 12-month-old specimen of several larger species of crocodilians. Large adults of this species can weigh up to 37 kg (82 lb). Cuvier's dwarf caiman has strong body armor on both its dorsal (upper) and ventral (lower) sides, which may compensate for its small body size in reducing predation. The dermal scales providing this protection have a bony base and are known as osteoderms.

The head has an unusual shape for a crocodilian, with a dome-shaped skull and a short, smooth, concave snout with an upturned tip, the shape rather resembling the head of a dog. The upper jaw extends markedly further forward than the lower jaw. …

Cuvier's dwarf caiman is native to tropical northern and central South America. It is present in the drainages of the Orinoco River, the São Francisco River, and the Amazon River, and the upper reaches of the Paraná River and the Paraguay River. The countries in which it is found include Peru, Ecuador, Colombia, Venezuela, Guyana, Suriname, French Guiana, Brazil, Bolivia, Trinidad and Paraguay. The range of this species is rather larger than that of the sympatric smooth-fronted caiman, as it extends into Paraguay and includes a larger area of Brazil. They also follow seasonal fluctuations in water-level, while the smooth-fronted caiman does not, which may explain how the two species are able to live in sympatry. Cuvier's dwarf caiman is a freshwater species and is found in forested riverine habitats and areas of flooded forest around lakes. It seems to prefer rivers and streams with fast-flowing water, but it is also found in quiet, nutrient-poor waters in Venezuela and southeastern Brazil. It is able to travel quite large distances overland at night and subadult individuals have sometimes been found in isolated, temporary pools. In the northern and southern parts of its range, it is also found in gallery forests in savanna country, but it is absent from such habitats in the Llanos and the Pantanal. …

These caimans are mainly nocturnal. Because they occupy many different microhabitats, their diet is believed to vary regionally. Adults feed on fish, amphibians, small mammals, reptiles, birds, crabs, shrimp, molluscs, insects, and other invertebrates, which they catch in the water or on land. Juveniles eat fewer fish, but also consume aquatic & shoreline insects, crustaceans, tadpoles, frogs, and snails, as well as land invertebrates, such as beetles. The prey is mostly swallowed whole and is ground up by stones in the gizzard. In the Pantanal, Cuvier's dwarf caiman estivates in burrows during the dry season and is able to maintain its temperature around 22 °C (72 °F) for days at a time.

Adult Cuvier's dwarf caimans are usually found singly or in pairs. The breeding of this species has been little studied, but it does not appear to be seasonal in nature. The female builds a mound nest out of vegetation and mud somewhere in a concealed location and lays a clutch of 10 to 25 eggs, hiding them under further vegetation. Nest temperature varies between 78–88 °F (26–31 °C) and are heated by decaying vegetation. The incubation period is around 90 days and the sex of the hatchlings depends on the temperature of the nest during that time. When the eggs begin to hatch, the female opens the nest in response to the calls made by the young. …

The genus name Paleosuchus is derived from the Greek palaios meaning "ancient" and soukhos meaning "crocodile". This refers to the belief that this crocodile comes from an ancient lineage that diverged from other species of caimans some 30 million years ago. The specific name palpebrosus is derived from the Latin palpebra meaning "eyelid" and osus meaning "full of". This refers to the bony plates (palpebrals) present on the upper eyelids. Common names include the musky caiman, the dwarf caiman, Cuvier's caiman, and the smooth-fronted caiman, although the last of these is also used to refer to the closely related P. trigonatus. In the pet trade, it is sometimes referred to as the wedge-head caiman.