Remnants of the age when reptiles ruled the world, today's crocodilians (alligators, caimans, and crocodiles), when seen in the wild, generally inspire awe, respect, a bit of fear, and a great deal of curiosity.
Recent classification schemes include a total of 23 species, distributed over most tropical and sub-tropical areas of the continents. Only two are found in Belize and northern Guatemala: The AMERICAN CROCODILE, which is the most widely distributed of the four New World crocodile species, and MORELET'S CROCODILE. There is a small population of American Crocodiles in southern Florida (USA), but mainly they range from Mexico, Central America and the Caribbean islands south to Colombia, Venezuela, Peru, and Ecuador. American Crocodiles can reach lengths of 7 meters (21.5 ft), as large as any crocodilian species, but in the wild individuals over 4 meters (13 ft) are now rare. American Crocodiles occur mostly in Belize's coastal areas, in both brackish and freshwaters habitats such as river mouths and mangrove swamps, but sometimes spread up rivers further inland. Morelet's Crocodile is found only in the Yucatn Peninsula region - southern Mexico, Belize, and Guatemala. These crocs are smaller than American crocs, most now obtaining lengths of no more than 2.5 meters (8 ft). Morelet's Crocodiles inhabit inland freshwater sites in Belize and northern Guatemala, such as lagoons, marshy parts of lakes, and sluggish rivers. (A third, smaller, species, the CAIMAN, or SPECTACLED CAIMAN, probably the most abundant crocodilian in the New World, occupies Guatemala's Pacific coastal region.)
Generally, differences in coloring are not a good way to distinguish crocodilians - most are shades of brown or olive-brown. Anatomy and location are more useful clues. Snouts of alligators and caiman tend to be broad and rounded, whereas those of crocodiles are longer and more pointed. Also, in crocodiles, the fourth tooth of the lower jaw projects upwards outside the mouth and can be seen above the upper jaw. Morelet's and American Crocodiles can be distinguished by location and, where they might overlap in distribution, by the Morelet's wider snout and generally smaller size. Male crocodilians, in general, are larger than females of the same age.
American Crocodiles sometimes excavate burrows along waterways, into which they retreat to escape predators and, when water levels fall too low, to estivate (sleep until water conditions improve). Crocodilians may use vocal signals extensively in their behavior, in communicating with one another, but their sounds have been little-studied. It is known that juveniles give alarm calls when threatened, and that parents respond by quickly coming to their rescue.
One might guess that among such primitive reptiles, parental care would be absent - females would lay eggs, perhaps hide them, but at that point the eggs and hatchlings would be on their own. Surprisingly, however, crocodilians show varying degrees of parental care. Nests are guarded and one or both parents often help hatchlings free themselves from the nest. In some species, such as the AMERICAN ALLIGATOR, parents also carry hatchlings to the nearest water. Females may also remain with the young for up to two years, protecting them. This complex parental care in crocodilians is sometimes mentioned by scientists who study dinosaurs to support the idea that dinosaurs may have exhibited complex social and parental behaviors.
Crocodilians are long-lived animals, many surviving 60+ years in the wild and up to 90+ years in zoos.
Breeding. During courtship, male crocodilians often defend aquatic territories, giving displays with their tails - up-and-down and side-to-side movements - that probably serve both to defend the territory from other males and to court females. Typically the female makes the nest by scraping together grass, leaves, twigs, and sand or soil, into a pile near the water's edge. She then buries 20 to 30 eggs in the pile that she, and sometimes the male, guard for about 70 days until hatching. Nests of the AMERICAN CROCODILE are a bit different. The female digs a hole in sandy soil, deposits her eggs, then covers them with sand, which she packs down. She guards the nest and often helps the young emerge. As in the turtles and some lizards, the sex of developing crocodilians is determined largely by the temperature of the ground around the eggs: males develop at relatively high temperatures, females at lower temperatures (see p. x - in turtle section). Crocodile young from a brood may remain together in the nest area for up to 18 months. Breeding seasons for crocodilians vary, with nesting observed during both wet and dry parts of the year; however, in the two species considered here, eggs are commonly laid in the Yucatan region from March through June.
Ecological Interactions. Somewhat surprisingly, crocodilians are prey for a number of animals. Young, very small crocodiles are eaten by a number of predators, including birds such as herons, storks, egrets and anhingas, and mammals such as raccoons and possibly foxes. Large adults apparently have only two enemies: people and large anaconda snakes. Slow-movers on land, crocodiles are sometimes killed by automobiles. Cases of cannibalism have been reported.
Owing to their predatory nature and large size, crocodilians play large roles in the history and folklore of many cultures, going back at least to ancient Egypt, where a crocodile-headed god was known as Sebek. The Egyptians apparently welcomed crocodiles into their canals, possibly as a defense from invaders. It may have been believed by Egyptians and other African peoples that crocodiles caused blindness, probably because the disease called river blindness results from infestation with a river-borne parasitic roundworm. To appease the crocodiles during canal construction, a virgin was sacrificed to the reptiles. Indeed, providing crocodiles with virgins seems to have been a farily common practice among several cultures, showing a preoccupation with these animals. Even today, carvings of crocodiles are found among many relatively primitive peoples, from South America to Africa to Papua New Guinea. The ancient Olmecs of eastern Mexico also had a crocodile deity. Crocodile remains have been found at Mayan ruin sites in both southern Mexico (on the island of Cozumel, for instance) and in Belize, suggesting that these ancient groups made use of the large reptiles for food and/or ceremonially.
This is an excerpt from the author's Belize and Northern Guatemala: The Ecotravellers' Wildlife Guide, (Academic Press, 1998). Contact the author via email at firstname.lastname@example.org..
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