The yacare caiman (Caiman yacare), also known commonly as the jacare caiman, Paraguayan caiman, piranha caiman, red caiman, and southern spectacled caiman, is a species of caiman, a crocodilian in the family Alligatoridae. The species is endemic to Argentina, Bolivia, Brazil, and Paraguay. Brown in color and covered with dark blotches, males grow to a total length (including tail) of and weigh around ; while females grow to long and about . 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. Its specific name, yacare, comes from the word jacaré, which means "alligator" in Old Tupi and then assimilated into Portuguese. 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.
Description
C. yacare is a medium-sized caiman, brown in color. Male specimens grow to in total length (including tail) and up to in weight. Females are much smaller, with an adult total length of and weight of . The average snout–vent length (SVL) of hatchlings is for females and for males. 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." Based on a study of the growth of multiple specimens in the Pantanal from 1987 to 2013, both sexes are about SVL at age five. By age 15, they have mostly finished growth, with females being about SVL and males over SVL. The study also showed that individuals have significant variation in their growth rates.
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. 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. Some of the teeth on its lower jaw can poke through holes in its upper jaw. This feature makes its teeth more prominent and has been compared to piranhas, which has established the common name "piranha caiman".
Ecology
The yacare caiman is ecologically similar to the spectacled caiman. It lives in semi-aquatic habitats, including lakes, rivers, and wetlands, but is able to adapt to a variety of habitats. Individuals sometimes move to different locations in groups if their habitat is disturbed. The species' diet consists of aquatic animals, such as snails and fish, and occasionally snakes. It has also been known to eat capybaras. When hunting for snails, this caiman looks within vegetation floating in water and uses its jaws to break the shells of the snails. 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.