American crocodile facts for kids

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American crocodile
Scientific classification
Kingdom: Animalia
Class: Sauropsida
Order: Crocodilia
Family: Crocodylidae
Genus: Crocodylus
Binomial name
Crocodylus acutus

The American crocodile is a species of crocodile that lives in the Americas, from the southern United States to northern South America. Its scientific name, Crocodylus acutus, means "Pointy-snouted crocodile", for the shape of its snout.

American crocodiles feed mostly on fish, but large individuals may prey on larger animals, such as deer. The crocodile looks like it is a log, and hides beneath the surface of the water. When the deer comes down to the water to drink, the crocodile lunges out of the water, grabs the deer in its jaws, and pulls it underwater, where it drowns.

After the deer is dead, the crocodile will grab a piece of meat in its jaws and spin around in a "death roll". American crocodiles are a somewhat aggressive crocodile species, and have been known to attack humans. Attacks on humans are rare, but happen most often in Mexico.

The American crocodile's range in southern Florida overlaps with that of the closely related American alligator. However, while the American alligator's range stretches as far north as Virginia, the American crocodile's range in the United States is confined to southern Florida. This is because alligators are much better at tolerating cold weather than crocodiles. The body temperature of alligators has been known to drop to 38 degrees Fahrenheit without any harm at all to the alligator. However, the American crocodile is better at tolerating saltwater than the alligator. American crocodiles have regularly been sighted 140 miles away from shore in the Caribbean Sea.

Characteristics

Museum of Science, Boston, MA - IMG 3224
Large American crocodile skull
Large american crocodile
Adult American crocodile

Like all crocodilians, the American crocodile is a quadruped, with four short, stocky legs, a long, powerful tail and a scaly hide with rows of ossified scutes running down its back and tail. Its snout is elongated and includes a strong pair of jaws. 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. Camouflage also helps it prey on food. The snout is relatively longer and narrower than that of the American alligator (Alligator mississippiensis), although broader on average than that of the Orinoco crocodile (C. intermedius). American crocodiles are also paler and more grayish than the relatively dark-hued American alligator. This crocodile species normally crawls on its belly, but it can also "high walk". Larger specimens can charge up to nearly 10 mph (16 km/h). They can swim at as much as 20 mph (32 km/h) by moving their bodies and tails in a sinuous fashion, but they cannot sustain this speed.

The American crocodile is sometimes confused with the smaller, Central American Morelet's crocodile, a smaller species that is native to Mexico.

Size

American crocodile
American crocodile

New hatchlings are about 27 cm (10.6 in) in length and about 60 g (2.1 oz) in mass. The average adult in the continental rivers can range from 2.9 to 4 m (9 ft 6 in to 13 ft 1 in) long and weigh up to 382 kg (842 lb) in males, while females can range from 2.5 to 3 m (8 ft 2 in to 9 ft 10 in) and weigh up to 173 kg (381 lb), 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.

Two biologists working with the History Channel series MonsterQuest spotted and filmed an American crocodile they estimated to be 5 to 5.5 m (16 ft 5 in to 18 ft 1 in), deep within Everglades National Park in Florida.

Distribution and habitat

Crocodile and Gator at Mrazek Pond (2), EVER, NPSPhoto, SCotrell, 4-2011 (9255694189)
American crocodiles (left) and American alligators (right) are usually tolerant of one another in places where they co-exist, such as this sand pond in Florida. However, they sometimes compete with each other for food and other resources

The American crocodile's range in southern Florida overlaps with that of the closely related American alligator. However, while the American alligator's range stretches as far north as Virginia, the American crocodile's range in the United States is confined to southern Florida. This is because alligators are much better at tolerating cold weather than crocodiles. The body temperature of alligators has been known to drop to 38 degrees Fahrenheit without any harm at all to the alligator. However, the American crocodile is better at tolerating saltwater than the alligator. American crocodiles have regularly been sighted 140 miles away from shore in the Caribbean Sea.

American Crocodile in Jamaica
American crocodile found in Jamaica's Black River
Large group of american crocodiles
Large group of American crocodiles in Cuba

American crocodiles in the United States coexist with the American alligator, and are primarily found south of the latitude of Miami, in Everglades National Park, Florida Bay, Biscayne Bay, and the Florida Keys. A sizable population occurs near Homestead, Florida, at the Turkey Point Nuclear Generating Station. Some individuals wander northward to warm summer waters and have been sighted in Sarasota County and Palm Beach County. In the summer of 2008, a crocodile was captured in the surf on Isle of Palms, South Carolina. In 2013, a 700-pound crocodile was captured in Tarpon Springs, Florida. Florida Fish & Wildlife Conservation Commission program staff note that the crocodile was not weighed to be 700 lbs. The weight was estimated by the nuisance alligator trapper who inadvertently caught the animal using a baited hook. American crocodiles of similar lengths have been accurately weighed at 450–500 lbs.

Biology and behavior

American crocodiles are more susceptible to cold than American alligators. While an American alligator can survive in water of 7.2 °C (45.0 °F) for some time, an American crocodile in that environment would become helpless and drown. American crocodiles, however, have a faster growth rate than alligators, and are much more tolerant of salt water.

American Crocodile, Costa Rica
American Crocodile, Costa Rica

Cleaning symbiosis involving the American crocodile as client has been described. Unlike the Old World crocodiles, which are sometimes cleared of parasites by birds, the American crocodile relies more on fish for parasite removal.

Hunting and diet

Crocodylus acutus head
Adult male C. acutus

The snout of the American crocodile is broader than some specialized fish-eating crocodilians and the freshwater crocodile, allowing it to supplement its diet with a wider variety of prey. In addition the snout gets even broader and bulkier as the animal matures, a sign for a shift in prey items.

Prey species have ranged in size from the insects taken by young American crocodiles to full-grown cattle taken by large adults, and can include various birds, mammals, turtles, crabs, snails, frogs, and occasionally carrion.

In Haiti, hatchling and juvenile American crocodiles lived primarily off of fiddler crabs (Uca ssp.), making up 33.8% and 62.3% of the diet by weight, respectively.

Elsewhere, aquatic insects and their larvae and snails are near the top of the food list for American crocodiles at this very early age. Immature and subadult American crocodiles, per a study in Mexico, have a more diverse diet that can include insects, fish, frogs, small turtles, birds and small mammals.

In Florida, bass, tarpon (Megalops atlanticus) and especially mullet, large crabs, snakes, mammals that habit the riparian and coastal regions of the Everglades, such as opossums and raccoons appeared to be the primary prey of subadult and adult American crocodiles.

In Haiti, adults appeared to live largely off of various birds (many of which are breeding large waders and other water birds such as heron, storks, flamingos, pelicans, grebes, coots and moorhens, followed by concentrations of marine fish including Tilapia and Cichlasoma, at times being seen to capture turtles, dogs and goats.

Interspecies predatory relations

Adult American crocodiles have no natural predators and almost any terrestrial or riparian animal they encounter is potential prey. American crocodiles are known predators of lemon sharks, and sharks avoid areas with American crocodiles.

American alligators and American crocodiles do not often come into conflict in the wild normally, due largely to habitat partitioning and largely separate distributions. In areas where the two species coexist, the smaller but more aggressive Cuban crocodile is behaviorally dominant over the larger American crocodile. In Mexico some Morelet's crocodile individuals have escaped from captivity, establishing feral populations and creating a problem for the populations of American crocodile, which must compete with this invasive species.

Reproduction

Juvenile American Alligator lying on a juvenile American Crocodile 2
Juvenile American Alligator lying on a juvenile American Crocodile at "Gatorama" in Palmdale, Florida.

American crocodiles breed in late fall or early winter, engaging in drawn-out mating ceremonies in which males emit very low frequency bellows to attract females.

Body size is more important than age in determining reproductive capabilities, and females reach sexual maturity at a length of about 2.8 m (9.2 ft). In February or March, females will begin to create nests of sand, mud, and dead vegetation along the water's edge. Nest location is crucial, and with the correct amount of vegetation, the eggs will develop within a small temperature range.

Because sex determination is temperature-dependent in crocodilians, slight changes in temperature may result in all-male or all-female clutches, which would possibly harm the health of the population.

About one month later, when it is time to lay, the female will dig a wide hole diagonally into the side of the nest and lay 30 to 70 eggs in it, depending on her size. After laying, the female may cover the eggs with debris or leave them uncovered. The white, elongated eggs are 8 cm (3.1 in) long and 5 cm (2.0 in) wide and have a number of pores in the brittle shell.

During the 75- to 80-day incubation period, the parents will guard the nest, often inhabiting a hole in the bank nearby. Females especially have been known to guard their nests with ferocity. But in spite of these precautions, American crocodile eggs sometimes fall prey to raccoons (Procyon sp.) (arguably the most virulent natural predator of crocodilian nests in the Americas), coatis, foxes, skunks or other scavenging mammals (even coyotes (Canis latrans) in Mexico and American black bears (Ursus americanus)) in south Florida), as well as large predatory ants, crabs and vultures. In Panama, green iguana (Iguana iguana) were seen to dig up and prey on American crocodile eggs occasionally, although in several cases were caught by the mother American crocodile and subsequently consumed. Crocodilian eggs are somewhat brittle, but softer than bird eggs. Young of this species hatch after 75–80 days.

Crocodylus acutus01
An American crocodile hatchling in Colombia

This species exists mostly in tropical areas with distinct rainy seasons, and the young hatch near the time of the first rains of the summer (July–August), after the preceding dry season and before the bodies of water where they live flood. During the hatching process, when the young American crocodiles are most vulnerable to predation, they will instinctively call out in soft, grunt-like croaks. These sounds trigger the female to attend to the nest, uncovering the eggs if they have been covered. Then she will aid the hatchlings in escaping their eggs and scoop them up with her mouth, carrying them to the closest water source.

The hatchlings, which are 24 to 27 cm (9.4 to 10.6 in) in length, have been reported to actively hunt prey within a few days of hatching. It is not uncommon for the mother to care for her young even weeks after they have hatched, remaining attentive to their calls and continuing to provide transportation. About five weeks after hatching, the young American crocodiles disband in search of their own independent lives.

Conservation status

Crocodylus acutus feeding
Crocodylus acutus in La Manzanilla, Jalisco, Mexico

Due to hide hunting, pollution, loss of habitat, and removal of adults for commercial farming, the American crocodile is endangered in parts of its range. In 1972, Venezuela banned commercial crocodile skin harvesting for a decade, as a result of 1950s and 1960s overhunting.

One thousand to 2,000 American crocodiles live in Mexico and Central and South America, but populations are data deficient. The American crocodile is considered a vulnerable species, but has not been assessed since 1996. It has an estimated wild population of 500 to 1,200 in southern Florida. On March 20, 2007, the United States Fish and Wildlife Service declassified the American crocodile as an endangered species, downgrading its status to "threatened"; the reptile remains protected from illegal harassing, poaching, or killing under the federal Endangered Species Act. In southern Florida, 67.8% of American crocodile mortality was attributed most likely to road collisions (found dead by the road), 10.5% were due to intentional killing and only 4.9% could be contributed to natural causes (the remaining balance were causes unknown).

Relationship with humans

See also: Crocodile attacks

American crocodiles are dangerous to humans; attacks in Mexico, Costa Rica, and Panama are not unprecedented.

Crocodiles are, as a general rule, more aggressive than alligators, at least towards humans.


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