Yacare caiman

The yacare caiman (Caiman yacare), also known commonly as the jacare caiman, Paraguayan caiman, piranha caiman, red caiman,<ref name="beardsley" /> and southern spectacled caiman,<ref name="crocodilian" /> is a species of caiman, a crocodilian in the family Alligatoridae. The species is indigenous to Argentina, Bolivia, Brazil, and Paraguay. Brown in color and covered with dark blotches, males grow to a total length (including tail) of Template:Cvt and weigh around Template:Cvt; while females grow to Template:Cvt long and about Template:Cvt.<ref name="growth" /> Typical habitats of this caiman include lakes, rivers, and wetlands. Its diet primarily consists of aquatic animals, such as snails, and occasionally land vertebrates. Mating occurs in the rainy season and eggs hatch in March, with young fending for themselves as soon as they hatch. The yacare caiman was hunted heavily for its skin to use for leather in the 1980s, which caused its population to decrease significantly. However, trading restrictions placed since have caused its population to increase. Its population in the Pantanal is about 10 million, and it is listed as least concern on the IUCN Red List.

Taxonomy

François Marie Daudin originally described the yacare caiman in 1802 as Crocodilus yacare.<ref name="biology" />Template:Rp Its specific name, yacare, comes from the word jacaré, which means "alligator" in Old Tupi and then assimilated into Portuguese.<ref name="crocodilian" />

The yacare caiman is one of three extant (living) species of the genus Caiman, the other two being the Spectacled caiman (Caiman crocodilus) and the Broad-snouted caiman (Caiman latirostris). There are also several extinct fossil species in the genus Caiman, possibly up to eight species. The yacare caiman is a member of the caiman subfamily Caimaninae, and is one of six living species of caiman.

As of 2010, the exact relationship between the yacare caiman and related species is unclear and complicated. There have been attempts to analyze this relationship, but these have not produced definite conclusions. It is sometimes considered a subspecies of the spectacled caiman (Caiman crocodilus), which would make its scientific name Caiman crocodilus yacare. These two species are the same morphologically, but are considered separate species due to their geographical differences.<ref name="action" />Template:Rp Its relationship to the spectacled caiman and the other extant caimans can be shown in the cladogram below, based on molecular DNA-based phylogenetic studies:<ref>Template:Cite journal</ref> Template:Clade

Description

C. yacare is a medium-sized caiman, brown in color.<ref name="beardsley" /> Male specimens grow to Template:Cvt in total length (including tail) and up to Template:Cvt in weight. Females are much smaller, with an adult total length of Template:Cvt and weight of Template:Cvt.<ref name="fao" /><ref name="biology" />Template:Rp The average snout–vent length (SVL) of hatchlings is Template:Cvt for females and Template:Cvt for males.<ref name="growth" /> National Geographic has described young individuals as "look(ing) like nothing more than tiny, windblown seeds floating amid the rushes at the edge of a lagoon in Brazil's remote interior."<ref name="geographic" /> Based on a study of the growth of multiple specimens in the Pantanal from 1987 to 2013, both sexes are about Template:Cvt SVL at age five. By age 15, they have mostly finished growth, with females being about Template:Cvt SVL and males over Template:Cvt SVL. The study also showed that individuals have significant variation in their growth rates.<ref name="growth" />

Dark marks are distributed across the body; most noticeably, its lower jaw is covered with three to five blotches. It has a smooth snout, which is medium in length and broad. It has lumps on its eyelids and a curved ridge between its eyes.<ref name="biology" />Template:Rp It has osteoderms on its scales, a feature also present in the spectacled caiman. It has an average of 74 teeth, with 5 pre-maxillary, 14–15 maxillary, and 17–21 mandibular.<ref name="crocodilian" /> Some of the teeth on its lower jaw can poke through holes in its upper jaw.<ref name="biology" />Template:Rp This feature makes its teeth more prominent and has been compared to piranhas, which has established the common name "piranha caiman".<ref name="beardsley" />

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  A juvenile, about one month old, in the Pantanal, Brazil
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  An up-close view of the head and frontal body, with its dark blotches visible
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  Taxidermied specimen
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  Heart displayed at the Museum of Veterinary Anatomy FMVZ USP

Ecology

The yacare caiman is ecologically similar to the spectacled caiman.<ref name="action" />Template:Rp It lives in semi-aquatic habitats, including lakes, rivers, and wetlands,<ref name="crocodilian" /> but is able to adapt to a variety of habitats. Individuals sometimes move to different locations in groups if their habitat is disturbed.<ref name="action" />Template:Rp The species' diet consists of aquatic animals, such as snails and fish, and occasionally snakes.<ref name="crocodilian" /> It has also been known to eat capybaras.<ref name="geographic" /> When hunting for snails, this caiman looks within vegetation floating in water and uses its jaws to break the shells of the snails.<ref name="beardsley" /> In July 1986, the stomach of a specimen in Bolivia was observed to be full of mud, along with small parts of eggshells that likely belonged to a caiman. In general, crocodilians can eat the eggshells of their own young subsequent to the young hatching.<ref name="museum" />

Breeding usually occurs in December–February, in the middle of the rainy season.<ref name="crocodilian" /> Nests are constructed by the females, built in a mound shape using mud and rotting vegetation.<ref name="beardsley" /> The species can lay as many as 44 eggs, but it most commonly lays 22–35, with the exact number often depending on the habitat type.<ref name="action" />Template:Rp It often exhibits multiple paternity, more so than several other crocodilian species.<ref name="mating" /> Females usually protect nests during incubation, but do so less when the human hunting pressure is high, ultimately causing a lower hatching success rate.<ref name="action" />Template:Rp Eggs hatch in March.<ref name="crocodilian" /> Young exhibit precociality, receiving very little help from their parents and having to care for themselves.<ref name="beardsley" /> They hide in grasses in the daytime, as herons and storks can eat young caimans.<ref name="geographic" /> Females become sexually mature at age 10–15.<ref name="growth" /> Similar species of the yacare caiman live to about age 50, which has been used as an estimate for this caiman's lifespan, but its exact lifespan is unknown.<ref name="beardsley" />

• Storks, such as this wood stork (right), can prey on juveniles (left).
  Storks, such as this wood stork (right), can prey on juveniles (left).
• An adult resting in the sun
  An adult resting in the sun
• Fish are a major part of the caiman's diet.
  Fish are a major part of the caiman's diet.
• Jaguars occasionally prey on caiman.
  Jaguars occasionally prey on caiman.

Distribution and conservation

File:Yacare Caimans (Caiman yacare) - Flickr - berniedup.jpg

Group of Yacare Caiman in Mato Grosso, Brazil

The range of the yacare caiman includes Argentina (north), Bolivia, Brazil (south), and Paraguay.<ref name="fao" /> It is one of three species of genus Caiman in South America, the others being the broad-snouted caiman (C. latirostris) and the spectacled caiman (C. crocodilus), with more easterly and northerly ranges, respectively. The yacare caiman is one of the most common species on its continent.<ref name="mating" />

In the 1980s, the species was "heading for oblivion" due to frequently being hunted for its skin;<ref name="geographic" /> hunters often went to water holes containing many yacare caimans and shot large numbers of them. They utilized the skin for leather and left the other parts of the carcasses at the water holes.<ref name="geographic" /> Although the species is covered with bony osteoderms, which had previously made it uncommon to be hunted for leather, it has some less bony spots which can be used for leather.<ref name="biology" />Template:Rp This practice caused the caiman's population to drop by the millions. In 1992, a ban was issued in Brazil that prohibited the trading of crocodilian skins. This resulted in a significant increase in its population, with about 10 million specimens living in the Pantanal alone as of 2013.<ref name="geographic" /> Current threats of the yacare caiman include deforestation, tourism, construction of dams and seaports, and illegal hunting.<ref name="geographic" /> The species reproduces quickly, which makes it less susceptible to hunting pressure.<ref name="crocodilian" />

The IUCN Red List designated the yacare caiman a species of least concern in 1996.<ref name="iucn status 19 November 2021" /> It is listed as threatened by the United States Fish and Wildlife Service as of June 5, 2000, after having been listed as endangered since June 2, 1970.<ref name="federal" /> As of 2010, it is listed as an Appendix II species by the Convention on International Trade in Endangered Species of Wild Fauna and Flora.<ref name="action" />Template:Rp

Further reading

• Daudin FM (1802). Histoire Naturelle, Générale et Particulière des Reptiles; Ouvrage faisant suite à l'Histoire Naturelle générale et particulière, composée par Leclerc de Buffon; et rédigée par C.S. Sonnini, membre de plusieurs sociétés savantes. Tome second. Paris: F. Dufart. 432 pp. (Crocodilus yacare, new species, p. 407). (in French and Latin).

External links

• Reichert, Michelle N., et al. (2018). "The respiratory mechanics of the yacare caiman (Caiman yacare Daudine) " [sic]. Journal of Experimental Biology 2018: jeb.193037. Template:Doi.