Cuvier's dwarf caiman
|Cuvier's dwarf caiman|
Cuvier's dwarf caiman (Paleosuchus palpebrosus), also known as Cuvier's smooth-fronted caiman or the musky caiman, is a small crocodilian from northern and central South America. It is found in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Surinam and Venezuela. It lives primarily near fast stretches of stream, but also in nutrient-deficient waters.
With a total length averaging 1.3–1.5 m (4.3–4.9 ft) in males and typically up to 1.2 m (3.9 ft) in females, it is not only the smallest extant species of the alligator and caiman family, but also the smallest of all crocodilians. The largest specimen on record measured 1.72 m (5.6 ft) in length. An adult will typically weigh around 6 to 7 kg (13.2 to 15.4 lb), around the same weight as a 6–12-month-old specimen of several larger species of crocodilians. Juvenile dwarf caimans eat invertebrates and small fish and frogs, while adult dwarf caimans eat fish, amphibians and invertebrates, such as large molluscs. It uses burrows as shelter during the day, and lays eggs on a mounded nest which hatch in about three months. They are sometimes kept as pets in captivity.
Cuvier's dwarf caiman was first described by the French zoologist Georges Cuvier in 1807. 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 caiman some thirty 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.
Cuvier's dwarf caiman is the smallest living New World crocodilian. Males grow to a maximum length of about 1.6 metres (5 ft 3 in) while females do not usually exceed 1.2 metres (3 ft 11 in) 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. The Cuvier's dwarf caiman has strong body armour on both the dorsal (upper) and ventral (lower) sides which may compensate for its small body size in reducing predation. 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. There are four pre-maxillary and fourteen to fifteen maxillary teeth on either side of the upper jaw and twenty-one or twenty-two teeth on each side of the lower jaw giving a total of about eighty teeth. The neck is relatively slender and the dorsal scutes are less prominent than in the smooth-fronted caiman (Paleosuchus trigonatus). The double row of scutes on the tail are small and project vertically. Adults are dark brownish-black with a dark brown head while juveniles are brown with black bands. The iris of the eye is chestnut brown at all ages and the pupil is a vertical slit.
Distribution and habitat
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, Surinam, French Guiana, Brazil, Bolivia 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.
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 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 sub-adult 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 savannah country, but it is absent from such habitats in Los Llanos and the Pantanal. Cuvier's dwarf caiman seems relatively tolerant of cool water compared to other species of crocodile. During the day, individuals sometimes lie up in burrows.
Adult Cuvier's dwarf caiman feed on fish, crabs, shrimps, molluscs and other invertebrates which they catch in the water or on land. Juveniles eat fewer fish but also consume crustaceans as well as land invertebrates such as beetles.
Adult Cuvier's dwarf caiman 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 from ten to twenty-five eggs. The incubation period is around ninety days and there are reports of adult caimans opening the nest and helping hatchlings to reach water. Newly emerged young have a coating of mucus and may delay entering the water until this has dried. Its continuing presence on their skin is believed to reduce algal growth.
Status and conservation
Many crocodilians are hunted for their skins but this is not the case with the Cuvier's dwarf caiman. This may be because the ventral skin in this species is too heavily armoured to make it easy to tan. Some individuals are killed by indigenous peoples for food and others, particularly in Guyana, are collected for the pet trade but there is no evidence that populations are dwindling as a result. There are some threats to this species from habitat destruction, including the mining of gold, but these are not thought to be of great significance. The estimated total population is over one million individuals.
In its Red List of Threatened Species, the IUCN lists Cuvier's dwarf caiman as being of "Least Concern". This is because its range is extensive, covering much of northern and central South America, and although its population trend is unknown, it appears to be abundant in many of the localities in which it is found. It is listed in Appendix II of CITES.
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- Paleosuchus CROCODILIANS Natural History & Conservation
- Cuvier's Dwarf Caiman, The Animal Files
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