| Caimans | |
|---|---|
 | |
| Yacare caiman,Caiman yacare | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Archosauria |
| Order: | Crocodilia |
| Family: | Alligatoridae |
| Subfamily: | Caimaninae Brochu, 1999 |
| Type genus | |
| Caiman Spix, 1825 | |
| Subgroups | |
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Acaiman (/ˈkeɪmən/ (also spelledcayman[3]) fromTaínokaiman[4][additional citation(s) needed]) is analligatorid belonging to thesubfamilyCaimaninae, one of two primary lineages within theAlligatoridaefamily, the other beingalligators. Caimans are native toCentral andSouth America and inhabitmarshes,swamps,lakes, andmangrove rivers. They have scaly skin and live a fairly nocturnal existence. They are relatively small-sizedcrocodilians with an average maximum weight of 6 to 40 kg (13 to 88 lb) depending on species, with the exception of theblack caiman (Melanosuchus niger), which can grow more than 4 m (13 ft) long and weigh more than 450 kg (990 lb). The black caiman is the largest caiman species in the world and is found in the slow-moving rivers and lakes that surround the Amazon basin. The smallest species is theCuvier's dwarf caiman (Paleosuchus palpebrosus), which grows to 1.2 to 1.5 m (3.9 to 4.9 ft) long. There are six different species of caiman found throughout the watery jungle habitats of Central and Southern America. The average length for most of the other caiman species is about 2 to 2.5 m (6.6 to 8.2 ft) long.
Caimans are distinguished from alligators, their closest relatives, by a few defining features: a lack of a bony septum between the nostrils, ventral armor composed of overlapping bony scutes formed from two parts united by a suture, and longer and sharper teeth than alligators. Caimans also tend to be more agile and crocodile-like in their movements.[5] The calcium rivets on caiman scales make their hides stiffer than those of alligators.
Several extinct forms are known, includingPurussaurus, a giantMiocene genus that grew to 7.6–10 m (25–33 ft)[6] and the 5.89 m (19.3 ft)Mourasuchus, which had a wideduck-like snout.[6]
Caimans are predators and, like alligators and crocodiles, their diet largely consists of fish. Caimans also hunt insects, birds, small mammals and reptiles.
Because of their large size and ferocious nature, caimans have few natural predators within their environments. Humans are their main predators, because the animals have been hunted for their meat and skin.Jaguars,anacondas andcrocodiles are the only other predators of caimans, although they usually prey on the smaller specimens or specific species of caiman such as theSpectacled Caiman andYacare caiman. During summer or droughts, caimans may dig a burrow and go into a form of summer hibernation calledaestivation.
Female caimans build a large nest in which to lay their eggs. The nests can be more than 1.5 m (4.9 ft) wide. Female caimans lay between 10 and 50 eggs, which hatch within about six weeks. Once they have hatched, the mother caiman takes her young to a shallow pool of water, where they can learn how to hunt and swim. The juveniles of spectacled caiman have been shown to stay together in pods for up to 18 months.[7]
Caimaninae iscladistically defined asCaiman crocodylus (thespectacled caiman) and all species closer to it than toAlligator mississippiensis (theAmerican alligator).[8][9] This is astem-based definition for caimaninae, and means that it includes morebasalextinct caimanine ancestors that are more closely related to living caimans than toalligators. The cladeJacarea includes the most derived caimans, being defined as the last common ancestor ofCaiman latirostris (Broad-snouted caiman),Caiman crocodilus (Spectacled caiman),Caiman yacare (Yacare caiman),Melanosuchus niger (Black caiman), and all its descendants.[1]
Below is acladogram showing thephylogeny of Caimaninae, modified from Hastingset al. (2013).[10]
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Here is an alternative cladogram from Bonaet al. 2018.[11]
| Alligatoridae |
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| (crown group) |
TheLate Cretaceous taxaStangerochampsa,Brachychampsa andAlbertochampsa have been previously referred to as stem-group caimans,[11][1] but Walter et al. (2022) recovered them as the basalmostalligatorines based on phylogenetic analysis and claimed that the earliest definitive stem-group caimans are known from theearliest Paleocene.[12] A different study by Adam Cossette and David Tarailo in 2024 recoveredBrachychampsa and relatives in a clade at the base of Caimaninae. They named this cladeBrachychampsini, defining it as "the largest clade of alligatorids more closely related toBrachychampsa montana than toCaiman crocodilus orAlligator mississippiensis".[2]
Extinctcrocodilians | |||||||||||||||||||||||||||||||||||||||||||
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