Caiman (other)

A caiman (; also cayman as a variant spelling from Taíno ''kaiman'') is an alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within the Alligatoridae family, the other being alligators. Caimans are native to Central and South America and inhabit marshes, swamps, lakes, and mangrove rivers. They have scaly skin and live a fairly nocturnal existence. They are relatively small-sized crocodilians with an average maximum weight of depending on species, with the exception of the black caiman (''Melanosuchus niger''), which can grow more than in length and weigh in excess of 450 kg (1,000 Ib). 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 the Cuvier's dwarf caiman (''Paleosuchus palpebrosus''), which grows to 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 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, plus caimans tend to be more agile and crocodile-like in their movements. The calcium rivets on caiman scales make their hides stiffer.

Several extinct forms are known, including ''Purussaurus'', a giant Miocene genus that grew to and the equally large ''Mourasuchus'', which had a wide duck-like snout.

Behavior

Caimans are predators and, like alligators and crocodiles, their diet largely consists of fish. Caimans also hunt insects, birds, small mammals and reptiles.

Due to 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 and crocodiles are the only other predators of caimans, although they usually prey on the smaller specimens or specific species of caiman such as the Spectacled Caiman and Yacare caiman. During summer or droughts, caimans may dig a burrow and go into a form of summer hibernation called aestivation.

Female caimans build a large nest in which to lay their eggs. The nests can be more than 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.

Phylogeny

Caimaninae is cladistically defined as ''Caiman crocodylus'' (the spectacled caiman) and all species closer to it than to ''Alligator mississippiensis'' (the American alligator). This is a stem-based definition for caimaninae, and means that it includes more basal extinct caimanine ancestors that are more closely related to living caimans than to alligators.

Below is a cladogram showing the phylogeny of Caimaninae, modified from Hastings ''et al.'' (2013).

Here is an alternative cladogram from Bona ''et al.'' 2018.

The Late Cretaceous taxa ''Stangerochampsa'', '' Brachychampsa'' and '' Albertochampsa'' have been previously referred to as stem-group caimans, but Walter et al. (2022) recovered them as the basalmost alligatorines based on phylogenetic analysis and claimed that the earliest definitive stem-group caimans are known from the earliest Paleocene.

Taxonomy

* Subfamily Caimaninae
** Genus †'' Acresuchus''
**Genus †'' Brachychampsa''
** Genus †''Bottosaurus''
** Genus †'' Centenariosuchus''
** Genus †''Chinatichampsus''
** Genus †''Protocaiman''
** Genus †'' Kuttanacaiman''
** Genus †'' Gnatusuchus''
** Genus †'' Culebrasuchus''
** Genus †'' Eocaiman''
** Genus †'' Globidentosuchus''
** Genus ''Paleosuchus''
*** ''P. palpebrosus'', Cuvier's dwarf caiman
*** ''P. trigonatus'', smooth-fronted caiman''
** Genus †''Mourasuchus''
** Genus †'' Necrosuchus''
** Genus †'' Orthogenysuchus''
** Genus †'' Tsoabichi''
** Genus ''Caiman''
*** ''C. yacare'', yacare caiman
*** ''C. crocodilus'', spectacled caiman
**** ''C. c. crocodilus'', spectacled caiman
**** ''C. c. apaporiensis'', Rio Apaporis caiman
**** ''C. c. fuscus'', Brown caiman
*** †''C. lutescens''
*** †'' C. venezuelensis''
*** †'' C. wannlangstoni''
*** †'' C. brevirostris''
*** ''C. latirostris'', broad-snouted caiman
** Genus ''Melanosuchus''
*** †'' M. fisheri''
*** ''M. niger'', black caiman

References

{{Taxonbar, from=Q478759

Alligatoridae
Selandian first appearances
Extant Selandian first appearances

mk:Кајмани