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black caiman
The black caiman (''Melanosuchus niger'') is a large crocodilian and, along with the American alligator, is one of the biggest extant members of the family Alligatoridae and order Crocodilia. It is a carnivorous reptile that lives along slow-moving rivers, lakes, seasonally flooded savannas of the Amazon basin, and in other freshwater habitats of South America. It is a quite large species, growing to sizes of at least and possibly up to in length, which make it the biggest reptile in the Neotropical ecozone.〔(Black Caiman (''Melanosuchus niger'') ). Crocodilian Specialist Group. Retrieved on 2013-04-13.〕〔(''Melanosuchus niger'' Black caiman ). Animal Diversity Web. Retrieved on 2013-04-13.〕 As their name implies, the black caiman has a dark coloration, as an adult. In some individuals the dark coloration can appear almost black. However they have grey to brown banding on the lower jaw. Juveniles have a more vibrant coloration compared to adults with prominent white to pale yellow banding on the flanks that remains present well into adulthood, at least more when compared to other species. The morphology is quite different from other caimans but the bony ridge that occurs in other caimans is present. The head is large and heavy; an advantage in catching larger prey.
The black caiman is the largest predator in the Amazon ecosystem, preying on a variety of fish, reptiles, birds and mammals.〔 They are generalists and apex predators, potentially capable of taking any animal within its range, including other predators.〔(Black Caiman, Black Caiman Skull ). Dinosaurcorporation.com. Retrieved on 2012-08-23.〕 Few ecological studies have been carried out on the species but it can be noted that the black caiman has its own ecological niche that enables coexistence without too much competition. As the largest predator in the ecosystem, it may also be a keystone species, playing an important role of maintaining the structure of the ecosystem.〔 Reproduction takes place in the dry season. Females build a nest mound with an egg chamber, protecting the eggs from predators. Hatchlings form groups called pods, guarded by the presence of the female. These pods may contain individuals from other nests. Once common, it was hunted to near extinction primarily for its commercially valuable hide. It is now making a comeback, listed as Conservation Dependent.〔 Overall a little-known species, it was not researched in any detail until the 1980s, when the leather-trade had already taken its toll.〔(Crocodilian Species – Black Caiman (Melanosucus niger) ). Crocodilian.com. Retrieved on 2012-08-23.〕 It is a dangerous species to humans and attacks have occurred in the past.〔
==Characteristics==
The black caiman has dark-coloured, scaly skin. The skin coloration helps with camouflage during its nocturnal hunts, but may also help absorb heat (see ''thermoregulation''). The lower jaw has grey banding (brown in older animals), and pale yellow or white bands are present across the flanks of the body, although these are much more prominent in juveniles. This banding fades only gradually as the animal matures. The bony ridge extending from above the eyes down the snout, as seen in other caiman, is present. The eyes are large, as befits its largely nocturnal activity, and brown in colour. Mothers on guard near their nests are tormented by blood-sucking flies that gather around their vulnerable eyes leaving them bloodshot.
The black caiman is structurally dissimilar to other caiman species, particularly in the shape of the skull. Compared to other caimans, it has distinctly larger eyes. Although the snout is relatively narrow, the skull (given the species' considerably larger size) is much larger overall than other caimans. Black caiman are relatively more robust than other crocodilians of comparable length. For example, a adult was found to have a considerably heavier and longer skull than a Nile crocodile (''Crocodylus niloticus'').〔Potts, Ryan J. (''Endangered Reptiles and Amphibians of the World – II. The Black Caiman, Melanosuchus niger'' ), Vermont Herpetology.〕 Young black caiman can be distinguished from large spectacled caiman by their proportionately larger head and shorter tail, as well as by the colour of the jaw, which is light coloured in the Spectacled caiman and dark with three black spots in the black caiman.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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