PYTHONS: Pythonidae

PHYSICAL CHARACTERISTICS

Some of the largest snakes in the world are pythons. One, the reticulated python, even holds the world's record for the longest wild snake at 33 feet (10.1 meters). That particular snake was killed in 1912 in Sulawesi, also known as Celebes, in Indonesia. Besides the reticulated python, however, only two other pythons grow to be longer than 20 feet (6.1 meters). In fact, the pygmy pythons of Australia are less than 2 feet (61 centimeters) long when full grown.

Pythons look much like boas. They both have cat's-eye pupils and little claw-like bits of bone, known as spurs, on each side of the vent, which is the slitlike opening on the belly side of the snake. They both also have heat vision and can "see" heat with little pits on the scales of their lips. Pythons and boas differ, however, in the location of these pits. In boas, they fall between scales, but a python's pits are in the middle of the scales. Both use the heat sensors to help them locate prey or food animals. Another major difference between the pythons and boas is that all pythons lay eggs, while all but three species of boas give birth to baby snakes.

Some pythons are almost completely one color, but many have patterns of blotches or bands on their backs. Often, the snake's scales are iridescent (IH-rih-DEH-sent), which means that they shine different colors depending on how the light hits them. A number of these snakes, including the Papuan python, can actually change color. This species can switch from having a bright yellow body and light gray head to completely dark brown from head to tail.

GEOGRAPHIC RANGE

Pythons are found in southern Asia; southeastern China and Southeast Asia; the Philippines; Papua, New Guinea, and Indonesia; and Australia. They also live in the central and southern region of Africa, which is known as Sub-Saharan Africa.

HABITAT

Depending on the species, pythons may live in thick forests, open forests, rainforests, rocky and scrubby areas high on hillsides, deserts, grasslands, swamps, or other freshwater areas. Some stay on land all their lives, while others spend much of their time climbing in trees. A few survive quite well in the desert, but others prefer the wetter areas, living in rainforests, or in some cases actually in a lake or other water area for up to six months a year.

DIET

Pythons are meat eaters and mostly feed on mammals and lizards, although some may take an occasional bird, and a few enjoy other species of snakes. They may crawl around looking for prey animals, but more often than not, they hunt by ambush. To ambush a prey, the snake remains still and waits for an animal to happen by and then lashes out to grab it.

Although it is very, very rare, some of the largest python species, including reticulated, African, and Indian pythons, have been known to coil around and then eat humans.

BEHAVIOR AND REPRODUCTION

Constriction (kun-STRIK-shun) is one of this family's best-known behaviors. After grabbing a prey animal in its jaws, the python wraps its body around the animal and constricts or squeezes so hard that the prey cannot breathe. When the animal dies or passes out, the snake uncoils and moves its head around to swallow the meal whole.

SEVEN NEW PYTHON SPECIES

In 2000 and 2001, the number of python species grew by seven. The seven new species resulted not when someone found a new snake in the field, but when scientists decided that they had wrongly lumped those seven species in with other python species. Once they were removed and given new species names, the python family grew from twenty-five species to thirty-two. As studies into this family continue, scientists expect that they may find more species hidden inside the thirty-two, and the python family will grow yet again.

When they feel threatened, many will hiss, ooze a bad-smelling material from the vent area at the beginning of the tail, and possibly strike and/or bite. The ball python gets its name because it curls up in a ball when it feels it is in danger.

Pythons are mostly active at night, although they often will sunbathe, or bask, during the daytime in a warm spot. One species, the diamond python of Australia, hibernates, or enters a deep sleep, during the winter to survive the cold months. Scientists know little more about python behavior.

Pythons are an egg laying species. Females of small species, such as the pygmy python, lay up to ten eggs at a time. Larger females, such as the reticulated python, may lay more than one hundred. The eggs usually stick together in a clump. Females coil their bodies around the eggs, which protects them from other animals and keeps them warm. Some mothers can even heat up their bodies during this time by tightening and loosening the muscles. Occasionally, a female may leave the eggs while she goes out to sunbathe and then return to wrap the eggs in her heated body. Once the eggs hatch, the baby snakes usually look much like the adults, although they are sometimes more brightly colored.

PYTHONS AND PEOPLE

People hunt pythons for their meat and skin and to make folk medicines. They are also popular in the pet trade, but most of the pet snakes now are born from other captive snakes rather than taken from the wild. Although some of the largest species are able to kill and eat humans, this hardly ever happens.

CONSERVATION STATUS

According to the World Conservation Union (IUCN), Ramsey's python of Australia is Endangered, which means that it faces a very high risk of extinction in the wild. The Asiatic rock python is listed as Near Threatened, which means that it is likely to qualify for a threatened category in the near future. The U.S. Fish and Wildlife Service also lists a certain group, called a subspecies, of the Indian python as Endangered, or in danger of extinction throughout all or a significant portion of its range. Overcollecting is a major problem for these snakes, and many countries now have strict rules in place to protect the pythons.

BLACK-HEADED PYTHON (Aspidites melanocephalus): SPECIES ACCOUNTS

Physical characteristics: The black-headed python has a shiny black head and neck on a beige body. Its body is striped with medium-to-dark brown bands. Adults usually reach no more than 5 feet (1.5 meters) in length.

Geographic range: This species lives across northern Australia.

Habitat: This snake usually remains in wooded areas, but some travel into rainforests, grasslands, and dry and rocky areas.

Diet: Black-headed pythons eat mostly lizards and other snakes, including venomous (VEH-nuh-mus) or poisonous species. They will also eat birds and mammals once in a while.

Behavior and reproduction: Active at night, this species spends part of its time in tunnels, or burrows, made by other animals. It is also able to dig burrows itself. The females, which are usually larger than the males, lay up to eighteen eggs at a time. Each egg measures about
3.5 inches (8.9 centimeters) long and hatches into a baby snake of approximately 2 feet (61 centimeters) in length. The babies look much like the adults but are more brightly colored. After four or five years, the young are old enough to have their own babies.

Black-headed pythons and people: Because it lives far away from people, the black-headed python and people rarely see or bother one another.

Conservation status: Although the World Conservation Union (IUCN) does not list it as threatened, scientists know little about the number of these snakes or how well they are surviving. ∎

GREEN PYTHON (Morelia viridis): SPECIES ACCOUNTS

Physical characteristics: The green python is bright green in color and may have a pattern of small blue markings, sometimes forming a thin stripe down its back. It may also have a few white, yellow, and/or black scales scattered here and there on the green back. It has long straight front teeth and a long tail. Adults usually range from 4.5 to 6 feet (1.4 to 1.8 meters) in length; a few reach more than 7 feet (2.1 meters).

Geographic range: The green python lives in New Guinea and several nearby islands. A small group also makes its home on the Cape York Peninsula of far northeastern Australia.

Habitat: The green python, which is also known as the green tree python, lives in forests, often climbing up and through tree branches.

Diet: Although they are capable of climbing, adults usually hunt on the ground. They eat mainly rats and other rodents, although they will also feed on a bird occasionally, capturing it with their long teeth. Young snakes, in particular, eat lizards.

Behavior and reproduction: This snake rests in branches much of the time by looping its body back and forth over a branch and drooping its head downward. This pose almost looks as if someone had rolled the snake into a spiral and carefully laid it over the limb. The snake is most active at night and does the majority of its hunting then. In one of its hunting tactics, it keeps its body still while wiggling just the tip of its tail. The motion lures in lizards, which the snake attacks and kills. Females, which are usually larger than males, have up to thirty eggs at a time. The 1.6–inch (4–centimeter) eggs hatch into young snakes that are 11 to 14 inches (28 to 36 centimeters) long. Young snakes may be bright red with scattered yellow and white scales or vivid yellow with small red and white markings. They switch to green as they grow older. Once they reach three years old, the young can start having their own babies.

Green pythons and people: Some people hunt this snake for its meat.

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

RETICULATED PYTHON (Python reticulatus): SPECIES ACCOUNTS

Physical characteristics: One of the largest snake species known, the reticulated python can reach as much as 33 feet (10.1 meters) long. Normally, however, adults are about 12 to 15 feet (3.7 to 4.6 meters), although 20-foot (6.1-meter) individuals are often found. The snake has a beautifully patterned back of yellow, black, and brown.

Geographic range: Its range includes the Philippines and Indonesia, India's Nicobar Islands, and much of Southeast Asia.

Habitat: The reticulated python usually lives in or near freshwater swamps, rivers, and lakes, often making its home in thick or open forests, caves, or rocky areas.

Diet: Also known as the regal python, it eats many animals, including monkeys, rats and other rodents, dogs and cats, pigs, deer, lizards, and large birds. They will also kill and eat humans, although this is very rare.

Behavior and reproduction: This snake spends a good deal of its time either climbing in trees or swimming in the water. It tends to be more active at night, especially if it lives near people. It rests in hiding places, such as burrows made by other animals, or inside hollow logs. The reticulated python hunts by either sneaking up on an animal or by remaining still and letting the animal come to it. Large females can lay more than one hundred eggs at a time, while smaller females lay less than two dozen.

Each egg, which measures 4 to 5 inches (10 to 13 centimeters) long, hatches into a 2- to 3-foot (61- to 91-centimeter) baby snake. The babies look like the adults. Once the young snakes reach their third or fourth year, they are old enough to start having babies of their own.

Reticulated pythons and people: People hunt this snake for its lovely skin, its meat, and for use in folk medicines. Some ranchers kill the snake because they are afraid it will eat their farm animals, while others destroy it because they worry it will eat their children or another person. In addition, the snakes are popular in the pet trade, although their large size soon makes them difficult to keep.

Conservation status: Reticulated pythons are not listed as endangered or threatened, but scientists know little about their numbers in the wild. ∎

FOR MORE INFORMATION

Books

Barker, David G., and Tracy M. Barker. Pythons of the World. Vol. 1. Australia. Lakeside, CA: Advanced Vivarium Systems, Inc., 1994.

Brazaitis, P., and M. Watanabe. Snakes of the World. New York: Crescent Books, 1992.

Cleave, Andrew. Snakes and Reptiles: A Portrait of the Animal World. New York: Magna Books, 1994.

Cogger, Harold G. Reptiles and Amphibians of Australia. Sydney, Australia: Reed New Holland, 2000.

Greene, Harry W. Snakes: The Evolution of Mystery in Nature. Berkeley: University of California Press, 1997.

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

Mattison, Chris. Snake: The Essential Visual Guide to the World of Snakes. New York: DK Publishing Inc., 1999.

McDonald, Mary Ann. Pythons. Minneapolis, MN: Capstone Press, 1996.

Minton, Sherman A., and Madge Rutherford Minton. Giant Reptiles. New York: Charles Scribner's Sons, 1973.

Murphy, John C., and Robert W. Henderson. Tales of Giant Snakes: A Historical Natural History of Anacondas and Pythons. Malabar, FL: Krieger Publishing Company, 1997.

O'Shea, Mark. A Guide to the Snakes of Papua New Guinea. Port Moresby, Papua, New Guinea: Independent Publishing Group, 1996.

Pope, Clifford Millhouse. The Giant Snakes: The Natural History of the Boa Constrictor, the Anaconda, and the Largest Pythons, Including Comparative Facts About Other Snakes and Basic Information on Reptiles in General. New York: Alfred A. Knopf, 1961.

Torr, Geordie. Pythons of Australia: A Natural History. Sydney, Australia: University of New South Wales Press, 2000.

Web sites

"Boas and Pythons." Singapore Zoological Gardens. http://www.szgdocent.org/cc/c-boa.htm (accessed on September 17, 2004).

"Green Tree Python." WhoZoo. http://www.whozoo.org/Intro98/jennglaz/jennglaz21.htm (accessed on September 17, 2004).

"Indian Python." Bagheera in the Wild. http://www.bagheera.com/inthewild/van_anim_python.htm (accessed on September 17, 2004).

"Pythons, Boas, and Anacondas: What's the Difference?" San Diego Zoo. http://www.sandiegozoo.org/animalbytes/t-python.html (accessed on September 20, 2004).

"Royal Python." Canadian Museum of Nature. http://www.nature.ca/notebooks/english/python.htm (accessed on September 17, 2004).