The American crocodile (Crocodylus acutus) is a species of crocodilian found in the Neotropics. It is the most widespread of the four extant species of crocodiles from the Americas, with populations present from South Florida, the Caribbean islands of Cuba, Jamaica, and Hispaniola, and the coasts of Mexico to as far south as Peru, Ecuador, Colombia, and Venezuela.
The habitat of the American crocodile consists largely of coastal areas. It is also found in river systems, but tends to prefer salinity, resulting in the species congregating in brackish lakes, mangrove swamps, lagoons, cays, and small islands. Other crocodiles also have tolerance to saltwater due to salt glands underneath the tongue, but the American crocodile is the only species other than the saltwater crocodile to commonly live and thrive in saltwater. They can be found on beaches and small island formations without any freshwater source, such as many cays and islets across the Caribbean. They are also found in hypersaline lakes; one of the largest known populations inhabits Lago Enriquillo in the Dominican Republic.
The American crocodile is one of the largest crocodile species. Males can reach lengths of more than , weighing over . On average, mature males are more in the range of in length weighing up to about . As with other crocodile species, females are smaller, rarely exceeding in length even in the largest-bodied population.
Like any other large crocodilian, the American crocodile is potentially dangerous to humans, but it tends not to be as aggressive as some other species. American crocodiles coexist with the American alligator in Florida, and with the smaller spectacled caiman within Central America and South America. The IUCN lists the American crocodile as vulnerable, and is a federally threatened, flagship species and ecological indicator within the Florida Everglades World Heritage Site.
Taxonomy and etymology The American crocodile was described by Georges Cuvier in 1807, and became known as the "sharp-snout alligator". In 1822, Constantine Samuel Rafinesque postulated that the species was in fact a crocodile.
The species was redescribed as Crocodylus floridanus by William Temple Hornaday in 1875, when Hornaday and C. E. Jackson were sent to Florida to collect alligator hides. Upon hearing of a "big old gator" in Arch Creek at the head of Biscayne Bay, Hornaday and his companions searched for it and reported:
In a few hours, we got sight of him, out on the bank in a saw-grass wallow. He was a monster for size—a perfect whale of a saurian, gray in color—and by all the powers, he was a genuine crocodile!
Crocodylus floridanus is now considered an invalid junior synonym of C. acutus.
Recent genetic assays indicate that Jamaican populations of the American crocodile may be genetically distinct from the sympatric Cuban crocodile, despite a significant history of hybridization. Further comparative genetic analyses of Caribbean populations of the American and Cuban crocodile indicate that insular populations of Cozumel and Banco Chinchorro crocodiles may be genetically distinct species.
Evolution Until 2020, the evolution of the American crocodile was poorly understood. However, the discovery of the Miocene species Crocodylus checchiai indicates that it, the Orinoco crocodile (Crocodylus intermedius), Morelet's crocodile (C. moreletii), and the Cuban crocodile (C. rhombifer) all share an ancestor hailing from Africa. The newly discovered animal may also represent the base of the evolutionary radiation of these animals, representing the missing link between crocodiles in Africa and the Americas.
The genus Crocodylus likely originated in Africa and radiated outward toward Southeast Asia and the Americas, although an Australia/Asia origin has also been considered. Phylogenetic evidence supports Crocodylus diverging from its closest recent relative, the extinct Voay of Madagascar, around 25 million years ago, near the Oligocene/Miocene boundary. American crocodile populations in Florida, Jamaica and Hispaniola (in the Dominican Republic) differ in gene frequencies. The only confirmed fossil of an American crocodile has been recovered from the Early/Middle Pleistocene Río Tomayate locality of El Salvador, although another find may have been recovered from Florida.
Below is a cladogram based on a 2018 tip dating study by Lee & Yates simultaneously using morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data, as revised by the 2021 Hekkala et al. paleogenomics study using DNA extracted from the extinct Voay.
Description
Like all true crocodilians, the American crocodile is a quadruped, with short, stocky legs; a long, powerful tail; and a scaly hide with rows of ossified scutes running down its back and tail. Individuals can be identified by using multiple dorsal scute patterns. The American crocodile has the most reduced dorsal osteoderms amongst all living crocodilians. Its snout is elongated and includes a strong pair of jaws. A , specimen had a bite force of . Its eyes have nictitating membranes for protection, along with lacrimal glands, which produce tears.
The nostrils, eyes, and ears are situated on the top of its head, so the rest of the body can be concealed underwater for surprise attacks. The snout is longer and narrower than that of the American alligator, but broader on average than that of the Orinoco crocodile. American crocodiles are also paler and more grayish than the relatively dark-hued American alligator. As juveniles, they bear distinct dark cross-marks but typically lose them with age.
The American crocodile is sometimes confused with the Morelet's crocodile, a smaller species that is native to Mexico.
American crocodiles have a distinctive bump halfway down the snout, in front of the eyes. This bump has been referred to as the "medial rostral boss", "medial preorbital hump", or "median preorbital elevation". The other 3 Crocodylus species of the Americas also have this feature, though to a lesser degree.
Size
New hatchlings are about in length and about in mass. The average adult in the continental rivers can range from long and weigh up to in males, while females can range from and weigh up to , the lower total length representing their average size at sexual maturity, the upper representing the expected upper size limit for the respective sex in most known populations. Common weights of adult American crocodiles in Florida may range from with corresponding lengths of . With extensive conservation efforts underway, there appears to be an increase in the number of large American crocodiles in Florida, some of the largest reportedly exceeding in length. Eight adult American crocodiles from Costa Rica ranged in total length from . Large adults of this species are capable of reaching in weight, with individuals approaching exceeding in weight, ranking it among the largest living crocodilians in the Neotropical realm. It is estimated that specimens of C. acutus measuring in TL would weigh around , specimens measuring in TL would weigh around , and specimens measuring in TL would weigh around . However, body mass can be fairly variable in mature adults. A large male specimen from Costa Rica measuring in total length weighed about . On the other hand, another specimen measuring in total length was found to have weighed
An individual named "Papillon" was considered to be one of the largest American crocodiles in captivity. It measured in length, weighed , and was estimated to be more than 80 years old when he died. The largest recorded female measured in length and weighed . Exceptionally large specimens may arguably exceed , possibly reaching or exceeding , but such specimens are unverified and possibly dubious although some are arguably supported by size projections from skull lengths. These exceptionally large crocodiles are estimated to range between in length and weigh between , though these are mere estimations and not verified.
Distribution and habitat
The American crocodile is the most widespread of the four extant species of crocodiles from the Americas. They are saltwater-tolerant, and have thus been capable of colonizing a multitude of islands within the Caribbean, and on some coastal Pacific islands as well making it the most widely distributed New World crocodile. They inhabit waters such as mangrove swamps, river mouths, fresh waters, and salt lakes, and can even be found at sea, hence their wide distribution throughout southern Florida, the Greater Antilles (excluding Puerto Rico and Isla de la Juventud, where they are replaced by the introduced spectacled caiman), Martinique, southern Mexico (including the Yucatán Peninsula), Central America, and the South American countries of Colombia, Peru, Venezuela (including on Margarita Island), and Ecuador. The American crocodile is especially plentiful in Costa Rica.
American crocodiles coexist with the American alligator in Florida and the spectacled caiman within Central America. The only other crocodiles present within the American crocodile's range are the Morelet's crocodile, and the critically endangered Cuban and Orinoco crocodiles. Recent morphological and genetic analyses have demonstrated hybridization with Cuban crocodiles among American crocodiles of the Yucatán.
Caribbean
One of its largest documented populations (the largest in the Caribbean) is in Lago Enriquillo, a hypersaline lake in the Dominican Republic. In Haiti, the only population known is in the brackish lake Etang Saumâtre, where the population is nearing extirpation due to overhunting and poaching (there is also a possible population that lives in l'Ester-Artibonite mangroves). In Jamaica, the species inhabits most of the swamps available, as well as brackish portions of rivers. American crocodiles have recently been sighted in Grand Cayman, leading experts to believe the species may be swimming from Cuba (which is home to a large American crocodile population) and slowly repopulating Grand Cayman. There have been reports of American crocodiles in Trinidad, however, those sightings are thought to have arisen due to the accidental translocation of the animal outside of its normal range. The species is thus not considered indigenous to Trinidad. Due to changing climate, which increases the frequency of hurricanes and cyclones in the Caribbean, American Crocodiles are reported to have decreased body condition. This is most likely due to the changes on the areas salinity, temperature and prey availability which could impede the recovery of these populations.
Florida The American crocodile's saline tolerance may have allowed it to inhabit limited portions of the United States, particularly southern Florida. Contrary to popular misinformation, the presence of the American alligator is not the reason the American crocodile was unable to populate brackish waters north of Florida, but rather the climate, as crocodiles are less tolerant of cold. Within the United States, the American crocodile's distribution is generally limited to the southern tip of Florida, though at least two have been found as far north as the Tampa Bay area. They are primarily found south of the latitude of Miami, in Everglades National Park, Florida Bay, Biscayne Bay, Dry Tortugas National Park and the Florida Keys. A sizable population occurs near Homestead, at the Turkey Point Nuclear Generating Station. Some individuals have been sighted in Palm Beach, Brevard, Pinellas and Sarasota counties. Their range in Florida is the only place in the world where alligators and crocodiles coexist.