ALLIGATORS AND CAIMANS: Alligatoridae

PHYSICAL CHARACTERISTICS

Like crocodiles, the alligators and caimans have a heavy body, with the back and tail covered by armor-like scales. Crocodiles, alligators, and caimans have a strong tail, which is at least as long as the rest of the body, and the back half of the tail often has a row of tall, ridged scales along the top. They also have a long snout, hind limbs larger than the front legs, and large, powerful jaws filled with teeth. Alligators and crocodiles are, however, different. All of an alligator's or caiman's lower teeth are hidden when its mouth is closed. In crocodiles, one lower tooth remains outside the jaw, even when it is clamped shut.

When alligators are young, they often have dark bands on their bodies, but these disappear as they get older. Adults may be dark gray, brown, black, or a bit yellowish. The smallest species is Cuvier's dwarf caiman, which grows to about 4 feet (1.2 meters). The largest is the American alligator, which can reach 13 feet (4 meters) long.

GEOGRAPHIC RANGE

Depending on the species, alligators and caimans may live in Central America, Mexico, the southeastern United States, South America, and/or eastern China.

HABITAT

Alligators and caimans are freshwater species that prefer still or slow-moving water, even if it is muddy or murky. Besides lakes, rivers, and streams, they are often found in swamps, marshes, and roadside ditches. Seven of the eight species live in the New World, which includes Central, South, and North America, but only one lives in the United States. The eighth species makes its home in a small area of eastern China, which is part of the Old World.

DIET

Alligators are meat-eaters, though they are anything but fussy about their prey. Youngsters will dine on snails and other invertebrates (in-VER-teh-brehts), which are animals without backbones. As they grow, they switch to the adult diet, which includes fishes, birds, small mammals, and other vertebrates (VER-teh-brehts), which are animals with backbones. They will also sometimes attack and devour smaller alligators and caimans. The larger species in this family are strong enough to kill a cow or deer for dinner.

Alligators hunt by ambush or by stalking. In ambush hunting, they remain still and wait for a prey animal to wander by. Stalking is usually done in the water. The alligator slowly and carefully swims closer and closer to a prey animal, perhaps a deer drinking at a watering hole, and then lunges forward to snap its jaws shut around the animal.

A LONG WINTER

The Chinese alligator has only a short time to mate, have babies, and eat enough to survive the year. The reason is the climate in which it lives. Chinese alligators make their home in the Yangtze River basin along China's central Atlantic coastline, an area that is cold much of the year. When temperatures drop in the late fall, the alligators slide into their winter burrows and stay there until the following April. They then crawl out to soak up the sun and warm their bodies. About a month later, the males begin to bellow, which starts the mating season. Females lay their eggs, which usually hatch in September, not long before the temperatures again cool and announce the coming of another long winter period in their burrows.

BEHAVIOR AND REPRODUCTION

A favorite daytime activity for alligators and caimans is sunbathing, or basking, on shore. They can also heat up their bodies by floating in the warm, upper surface of the water. When they need to cool off, they simply sink to colder, deeper water. Some live where the weather is especially cold at times during the year, but none of them actually hibernate (HIGH-bur-nayt), or become inactive and enter a state of deep sleep. Instead, these species either lie still in shallow water and breathe through the nose, the only part of the body not underwater, or they retreat into winter burrows to wait for spring.

Alligators and caimans appear very restful when they are basking, but they are actually quite alert. With a quick swipe of the tail, a swift turn of the head with jaws open, or a speedy charge on their powerful legs, they can change from a quiet, peaceful-looking reptile to a dangerous predator. Alligators and caimans can move in several ways. In the water, they usually swim by slowly swaying the tail from side to side. On land, they may crawl along with the belly and tail dragging on the ground, or they can do a "high walk" and run as a lizard does with the body held above the ground.

Alligators and caimans often live in groups. They get along well during most of the year, but during the spring breeding season, the rules change. Adults begin slapping their heads on the water surface or charging one another with their mouths wide open, although they do not normally bite. By summer, the females begin to scrape together piles of leaves on which they lay their 12 to 60 eggs. The mother remains nearby, and when the babies hatch one or two months later, she helps them out of the nest and to the water. In some species, the temperature of the nest decides the sex of the babies. Cool temperatures produce all females, and warm temperatures produce all males. Temperatures in the middle turn out males and females.

ALLIGATORS, CAIMANS, AND PEOPLE

People sometimes hunt alligators and caimans for their skin, their meat, and sometimes for their organs, which are used to make perfume. In Florida, Louisiana, and other places, they are an important tourist attraction and help bring in money to the local community.

CONSERVATION STATUS

The World Conservation Union (IUCN) considers the Chinese alligator to be Critically Endangered, which means that it faces an extremely high risk of extinction in the wild. It also lists the black caiman as Conservation Dependent, which means it still requires attention to make sure it survives. The U.S. Fish and Wildlife Service lists the American alligator, a U.S. species, as Threatened, or likely to become endangered in the foreseeable future. These and other alligators and caimans often suffer from habitat loss and overhunting, and numerous conservation efforts are under way to protect them.

AMERICAN ALLIGATOR (Alligator mississippiensis): SPECIES ACCOUNTS

Physical characteristics: A large reptile, the American alligator has a black or dark grayish green back and tail with a white belly. Young alligators have numerous yellow markings on the back and tail. American alligators are sometimes confused with American crocodiles, but the crocodile has a snout that becomes thinner at the tip. The alligator's snout remains wide. Adult American alligators usually grow to 8 to 13 feet (2.4 to 4 meters) long, but some giants may reach 19 feet (5.8 meters) or more.

Geographic range: American alligators live in the United States from North Carolina down to Florida and west to Texas.

Habitat: American alligators make their homes in still or slow-moving freshwater areas, including marshes and swamps, rivers, and lakes. Occasionally, they make their way into the swimming pools of people who live near their natural habitat.

Diet: Meat-eaters, they will dine on almost any animal they come across, including turtles, fishes, mammals, and sometimes smaller alligators. They swallow most smaller prey whole. For larger animals, however, the alligators first drown the victim, then chomp off mouthfuls of flesh.

Behavior and reproduction: American alligators live in groups, with great grandparents, grandparents, parents, and children often sharing the same area. During the spring breeding season, the males try to interest the females by bumping softly against them and calling out with loud bellows. The females bellow, too, but much less often and not quite as loudly. After mating, the female lays 36 to 48 eggs, which hatch about two months later. She helps the young out of the nest and to the water. The family stays together for two or three months, and sometimes up to three years. The young alligators are ready to become parents themselves when they reach about 10 years old. American alligators live to be 50 years old or older.

American alligators and people: In many areas, people like alligators because they bring money to the community through tourism, but at the same time dislike them because the reptiles sometimes eat pets or have to be removed from golf courses and swimming pools. Now that people have begun to move farther and farther into the alligators' habitat, attacks on humans have also become much more common. According to the Florida Fish and Wildlife Conservation Commission, alligator attacks on humans in that state from 1948 to 2003 numbered 326 and resulted in 13 deaths.

Conservation status: The World Conservation Union (IUCN) does not consider this species to be at risk, but the U.S. Fish and Wildlife Service lists it as Threatened or likely to become endangered in the foreseeable future. ∎

COMMON CAIMAN (Caiman crocodilus): SPECIES ACCOUNTS

Physical characteristics: Also known as the spectacled caiman, the common caiman has a bony ridge and slightly lighter color around each eye. Its body is greenish to brownish gray, sometimes with noticeable dark bands on its tail and patches on its back. Adults usually grow to 4 to 6 feet (1.2 to 1.8 meters) long, but some can reach up to 10 feet (3 meters) from the tip of the snout to the end of the tail.

Geographic range: The common caiman lives from southern Mexico to northern Argentina, on the islands of Trinidad and Tobago, and in southern Florida. Cuba and Puerto Rico also have introduced populations.

Habitat: It is found in calm freshwater lakes, rivers, and swamps, as well as man-made roadside ditches.

Diet: From youngsters to adults, common caimans tend to eat animals they find in the water. Although the youngest ones will eat insects and other invertebrates they find on land, juveniles are fond of snails, and adults mainly eat different types of fishes.

Behavior and reproduction: Common caimans live in groups quite peacefully for most of the year, but during the mating season, the males begin bellowing and set up territories. One male may mate with several females. The female lays 12 to 36 eggs in a leafy nest she makes on land. The male guards the nest until the babies hatch. The mother then carries them to the water. The family stays together for about a year.

Common caimans and people: People sometimes hunt this reptile for its meat and its skin.

Conservation status: This species is not considered endangered or threatened. ∎

FOR MORE INFORMATION

Books:

Lamar, William. The World's Most Spectacular Reptiles and Amphibians. Tampa, FL: World Publications, 1997.

Cleaver, Andrew. Snakes and Reptiles: A Portrait of the Animal World. Wigston, Leicester: Magna Books, 1994.

Lockwood, C. C. The Alligator Book. Baton Rouge: Louisiana State University Press, 2002.

Ross, C. A., ed. Crocodiles and Alligators. New York: Facts on File, Inc., 1989.

Rue, Leonard Lee. Alligators and Crocodiles. Wigston, Leicester: Magna Books, 1994.

Web sites:

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"Alligator." World Almanac for Kids. http://www.worldalmanacforkids.com/explore/animals/alligator.html (accessed on September 21, 2004).

"Alligator mississippiensis (DAUDIN, 1801)." Florida Museum of Natural History. http://www.flmnh.ufl.edu/cnhc/csp_amis.htm (accessed on December 15, 2004).

"Alligators and Crocodiles." San Diego Zoo. http://www.sandiegozoo.org/animalbytes/t-crocodile.html (accessed on September 21, 2004).

"Crocodilian Species List." Florida Museum of Natural History. http://www.flmnh.ufl.edu/cnhc/csl.html (accessed on December 15, 2004).

"The Reptiles: Alligators and Crocodiles." Nature. http://www.pbs.org/wnet/nature/reptiles/ (accessed on December 15, 2004).

"Spectacled Caiman." Enchanted Learning. http://www.enchantedlearning.com/subjects/reptiles/caiman/Speccaiman.shtml (accessed on September 21, 2004).

"Wild Things: The Not-So-Friendly Caiman." Kidzworld. http://www.kidzworld.com/site/p483.htm (accessed on September 21, 2004).