Cobras, Kraits, Sea Snakes, and Relatives: Elapidae
COBRAS, KRAITS, SEA SNAKES, AND RELATIVES: ElapidaeNORTH AMERICAN CORAL SNAKE (Micrurus fulvius): SPECIES ACCOUNTS
BLACK-NECKED SPITTING COBRA (Naja nigricollis): SPECIES ACCOUNTS
KING COBRA (Ophiophagus hannah): SPECIES ACCOUNTS
DEATH ADDER (Acanthophis antarcticus): SPECIES ACCOUNTS
SEA KRAIT (Laticauda colubrina): SPECIES ACCOUNTS
The cobras, kraits (KRYTS), sea snakes, death adders, and other members of this family are venomous (VEH-nuh-mus), or poisonous, snakes that vary in length from just 7 inches (17.8 centimeters) to 16 feet, 8 inches (5 meters). Despite their many differences, all of the snakes in this family, known as elapids (EH-luh-puds), are alike in some ways. They each have two "fixed" fangs, or long, pointed teeth that cannot move, at the front of the mouth. These short fangs are always pointed downward and ready to inject venom. Elapids are mostly thin snakes with heads that are about the same size around as their necks and with large scoots, or scales, down the back. Many cobras are well known for their ability to spread out their necks into a sort of hood.
Some elapids are brightly colored; others are not. Some have stripes, but others are just one color. Still others have side-to-side bands of color. The coral snakes, for example, often have bright bands of different colors.
This large family has species that can live in almost any habitat, from deserts and dry grasslands to rainforests and even oceans. Most of the three hundred species, or types of snakes, in this family live on the ground, but some elapids spend at least part of their time underground, and others live nearly their entire lives in trees or underwater. Some scientists split this family into two: the Elapidae encompassing all of the land-living species and a second family, known as the Hydrophiidae, containing the snakes that live in water.
Elapids eat small mammals, birds, snakes, lizards, frogs, and fishes. Many of them feed on whatever they can find, while others eat only one or two different items. The favorite food of the southern African Rinkhal's cobra, for instance, is toads. Sea snakes find their meals in the coral reefs where most of them live, and they eat mainly fishes, eels, or squids. Most species in this family actively hunt for food, slithering or swimming up to prey, an animal they intend to eat, and then striking at them and biting them with their fangs. The fangs release venom, or poison, which slows down the prey's heartbeat and breathing, making the animal easy to eat. Rather than finding prey, the Australian death adder lets prey come to it. The adder sits still, wriggling only the tip of its tail, which looks much like an insect grub, the very young form of an insect. As the animals come closer to take a bite out of the tasty "grub," the snake strikes.
Nature is filled with copycat animals, and snakes are no exception. The coral snake is one example. These snakes have powerful venom and, with one bite, can sicken and often kill attacking animals. They also have bold red, black, and yellow bands, and predators learn to avoid snakes with those patterns. There are other snakes that live among the coral snakes but lack their venom. Many of them are colored very much like the coral snakes. While these "copycats" pose little danger to other animals, predators avoid them because they look so much like coral snakes. These copycats, known as mimics (MIM-iks), can be quite common. In coral snake habitats, for instance, these mimic species are so common that they actually outnumber true coral snakes by two to one.
BEHAVIOR AND REPRODUCTION
One of the most common myths about elapids is that they can be "charmed," or controlled through playing music. Film clips show snake charmers playing the flute and cobras rising from their baskets because they have been "hypnotized," or put into a trance, by the music. Actually, cobras cannot even hear music. Like all elapids, they can hear low sounds, like the vibrations (vie-BRAY-shuns) made by a person stomping on the ground, but they cannot hear musical notes, which are much higher sounds. The cobra sways back and forth not because it is listening to the musical beat but because it is following the movements of the snake charmer, who is swaying to the music.
Depending on the species, an elapid may be active at sunset and at night or during the daytime. Snakes that live in warm climates stay active all year, but those that live in colder areas, hibernate (HIGH-bur-nayt), or remain inactive, in the winter. During hibernation (high-bur-NAY-shun), the snakes enter a state of deep sleep that helps them survive the cold weather.
Most elapids reproduce in the spring. In general, males fight with one another, and the winners mate with the females. Many elapids lay eggs, but others give birth to live young snakes. The egg-laying females usually place their eggs under a rock or a log or in some other hiding place. The eggs hatch in about three months. The females that give birth to live young do so in a hiding place. Scientists believe that the king cobras are the only elapids that provide any care for eggs or young. These snakes remain with their eggs and will strike out at anything or anyone who approaches too closely.
COBRAS, KRAITS, SEA SNAKES, THEIR RELATIVES, AND PEOPLE
More than half of the venomous snake species in the world belong to this family, which includes cobras, mambas, coral snakes, land-living kraits, brown snakes, taipans (TY-pans), death adders, sea kraits, and sea snakes. Some of them are quite deadly to humans. Nonetheless, snake charmers and other people annoy the snakes for entertainment or collect them for their skins, which are used for belt and shoe leather.
The World Conservation Union (IUCN) lists seven species as Vulnerable, which means that they face a high risk of extinction in the wild. Two species are Near Threatened, which means they are at risk of being threatened with extinction in the future. Causes for the declines in their numbers may include loss of their habitats, or preferred living areas, and collecting of snakeskins for leather.
Physical characteristics: This thin snake has a repeated color pattern of narrow yellow, wide red, and wide black bands. A narrow yellow band separates the black and red bands. Adults normally are 18 to 28 inches (45.7 to 71 centimeters) long, but they have been known to grow to more than 4 feet (1.2 meters).
Geographic range: North American coral snakes live in the United States and Mexico.
Habitat: The North American coral snake lives in many areas, including deserts and forests and even along the shorelines of lakes and ponds.
Diet: This snake eats mostly small lizards but sometimes also dines on frogs and other snakes. It tracks the lizards and snakes by following their scents (SENTS), or smells.
Behavior and reproduction: These secretive snakes often hide under leaves or logs or in some other shelter. When a coral snake feels threatened, it sometimes pokes out the end of its tail, which may confuse the attacker into thinking the tail is the head. This can give the coral snake time to get away. Females usually lay fewer than nine eggs at a time, but they can lay as many as thirteen. Little else is known about them.
North American coral snakes and people: The coral snake's venom is strong enough to kill a human, but antivenin (an-tee-VEH-nuhn) is available. Antivenin is a substance that neutralizes a snake's venom, meaning that it causes the venom to have no bad effect.
Conservation status: These snakes are not endangered or threatened. ∎
Physical characteristics: The black-necked spitting cobra may be solid black or brown, or it may be striped with black and white. It has two sharp, thin fangs that it uses to spray its venom. These snakes can reach a length of 79 inches (2 meters).
Geographic range: This snake lives in western, central, and southern Africa.
Habitat: The black-necked spitting cobra usually lives in grasslands, but it sometimes enters villages and cities, where it can cause quite an uproar among human residents, who worry about being poisoned with its venom.
Diet: The black-necked spitting cobra eats almost anything it finds, including frogs and toads, birds and their eggs, and other reptiles.
Behavior and reproduction: Although it spends much of its time on the ground, this cobra can easily climb into bushes and trees. It is most active at night, but it sometimes moves about during the day. Females lay eight to twenty eggs at a time.
Black-necked spitting cobras and people: Local people fear this snake, which can spray venom almost 10 feet (3 meters). The snake aims for the eyes, and the venom can be very painful and can even cause blindness if the person is not treated immediately. A bite from the snake can kill a person.
Conservation status: The black-necked spitting cobra is not endangered or threatened. ∎
Physical characteristics: The king cobras are snakes of many colors; they may be black, brown, brownish-green, or yellow. These large snakes usually reach about 9.8 feet (3 meters) in length, but they can grow to 16.4 feet (5 meters).
Geographic range: The king cobra lives from India through Southeast Asia (the Philippines and into Indonesia).
Habitat: King cobras are animals of the thick jungle and usually prefer to live near water.
Diet: Their main food items are other snakes, including other venomous species.
Behavior and reproduction: Unlike most other members of this family, male and female king cobras will form pairs, make a nest from leaves and dirt in a growth of bamboo, and protect the nest and, later, the eggs from attackers. Once the eggs hatch, the parents leave the nest site, and the young must live on their own immediately.
King cobras and people: When a king cobra bites a person, it can inject a dose of venom that can kill.
Conservation status: The king cobra is not endangered or threatened. ∎
Physical characteristics: The death adder has a thick body, with bands of light brown to black. Adults are about 20 to 39 inches (0.5 to 1 meter) long.
Geographic range: The death adder is found in Australia.
Habitat: Death adders live in dry areas, including grasslands and deserts, in eastern and southern Australia. It also sometimes wanders into cities.
Diet: The death adder eats mainly small reptiles but also frogs and small mammals.
Behavior and reproduction: Most members of this family actively search out prey to eat, but the death adder buries itself, leaving out just the tip of its tail. The tail tip, which looks like a worm, catches the attention of their prey. When the prey animals get close, the adder strikes. The death adder is a secretive snake and is most active at night. Females give birth to live snakes, instead of laying eggs; they may have up to twenty young at a time.
Death adders and people: The snake's venom is very strong and can kill people. Antivenin is available.
Conservation status: The death adder is not endangered or threatened. ∎
Physical characteristics: The sea krait is banded with blue or bluish gray and black and has a paddle-shaped tail to help it swim. It also has valves, or flaps, that can close its nostrils, or nose holes, when it goes underwater. Adults are usually about 39 inches (1 meter) long, but some sea kraits can reach 55 inches (1.4 meters) in length.
Habitat: Sea kraits spend most of their lives in the ocean water, coming ashore only to rest or to lay their eggs. Once in a while, they may travel into mangrove swamps. Mangroves are tropical trees and shrubs that form thick masses along coastlines.
Diet: They usually find their food, primarily eels, in coral reefs.
Behavior and reproduction: Most active at night, the sea krait occasionally looks for food in the daytime. In the breeding season, females leave their saltwater homes to lay up to eighteen eggs at a time on the seashore.
Sea kraits and people: People are rarely bitten by this gentle snake. A sea krait's bite, however, is venomous.
Conservation status: The sea krait is not endangered or threatened. ∎
FOR MORE INFORMATION
Branch, Bill. Field Guide to Snakes and Other Reptiles of Southern Africa. Sanibel Island, FL: Ralph Curtis Books, 1998.
Brazaitis, Peter, and Myrna E. Watanabe. Snakes of the World. New York: Crescent Books, 1992.
Broadley, Donald G. FitzSimons' Snakes of Southern Africa. Johannesburg, South Africa: Jonathan Ball, 1990.
Campbell, Jonathan A., and William W. Lamar. The Venomous Reptiles of Latin America. Ithaca, NY: Comstock Publishing Associates, 1989.
Cogger, Harold G. Reptiles and Amphibians of Australia. Sydney, Australia: Reed New Holland, 2000.
Creagh, Carson. Reptiles. Alexandria, VA: Time-Life Books, 1996.
George, Linda. Coral Snakes. Mankato, MN: Capstone Books, 1998.
Mattison, Chris. The Encyclopedia of Snakes. New York: Facts on File, 1995.
Montgomery, Sy. The Snake Scientist. Boston: Houghton Mifflin, 2001.
Spawls, Stephen, and Bill Branch. The Dangerous Snakes of Africa: Natural History, Species Directory, Venoms, and Snakebite. Sanibel Island, FL: Ralph Curtis Books, 1995.
"King Cobra." NationalGeographic.com. http://www.nationalgeographic.com/kingcobra/index-n.html (accessed on September 9, 2004).