Burmese Python (Python bivittatus): Facts, Size and Range

Appearance

The Burmese python has a thick, muscular body covered in smooth scales. Its background color is tan, light brown or gray, overlaid with a row of large, dark brown blotches edged in black that run down the back like an irregular jigsaw puzzle. Smaller blotches mark the sides. This pattern is superb camouflage on a forest floor scattered with leaves and shadows.

The head is fairly long and wedge-shaped, with a dark arrowhead or spear-point mark on top and a dark stripe running back from each eye. Along the lips are heat-sensitive pits that let the snake detect warm-blooded prey in total darkness. Like other pythons and boas, it has two small claw-like spurs beside the vent, the last external traces of the hind legs its ancestors had. Males have larger spurs than females. For the features that separate it from its look-alike relatives in the Americas, see python vs boa.

Until 2009, the Burmese python was usually treated as a subspecies of the Indian python (Python molurus), and older books still call it Python molurus bivittatus. It is now recognized as a separate species. The Indian python is generally lighter in color and lacks the clear arrowhead on the crown.

How big do Burmese pythons get?

The Burmese python is one of the giants of the snake world. In the wild, adults usually reach 2.5 to 5 m (8 to 16 ft), with an average of about 3.7 m (12 ft). Snakes longer than 5 m (16 ft) are rare. Females are only a little longer than males on average but much bulkier and heavier.

The longest wild Burmese python measured so far was a 5.79 m (19 ft) snake caught in Big Cypress National Preserve in July 2023. A captive female named Baby, measured at about 5.74 m (18 ft 10 in), reached a weight of 182.8 kg (403 lb), far heavier than any wild python ever weighed. Reports of wild Burmese pythons of 7 m (23 ft) or more have never been confirmed. Dwarf island forms on Java, Bali and Sulawesi stay much smaller, often around 2 m (6.5 ft). To see how this snake ranks against the reticulated python and the green anaconda, see our list of the largest snakes.

Habitat and range

The native range stretches from northeastern India, southeastern Nepal, Bhutan and Bangladesh through Myanmar, Thailand, Laos, Cambodia and Vietnam to southern China, including Hainan and Hong Kong, and south to Java, Bali, Sumbawa and southern Sulawesi in Indonesia.

Within this range the snake uses a wide variety of habitats: grassland, marshes and swamps, river valleys, rocky foothills, woodland and jungle with open clearings. The one constant is water. Burmese pythons are strong swimmers that can stay submerged for up to about 30 minutes, and they are rarely found far from a permanent stream, pond or wetland.

Young pythons climb well and spend much time in trees and shrubs. As they grow heavy, adults become mostly ground-dwelling. In the cooler northern parts of the range they may spend several weeks of winter inactive in a hollow tree, a riverbank burrow or under rocks, a state called brumation.

Diet and hunting

The Burmese python is a classic sit-and-wait predator. It lies motionless and camouflaged beside a trail or at the water’s edge, sometimes for days, until an animal comes close. Then it strikes, grips the prey with its many backward-curving teeth and throws several coils around it. Each time the prey breathes out, the coils tighten. Prey dies mainly because blood flow is cut off, not because bones are crushed.

Its diet is mostly mammals and birds: rats and other rodents, rabbits, civets, small deer, poultry and wading birds. Big pythons can swallow animals as large as pigs, goats or deer. In Florida, Burmese pythons have eaten raccoons, opossums, marsh rabbits, bobcats, white-tailed deer, wood storks and even American alligators.

Because it swallows prey whole, a python can survive on few meals. In Asia, adults typically feed every month or two and can fast for many months. After a big meal its body changes dramatically: within a day or two the intestines grow and the heart’s main chamber can enlarge by roughly 40 percent, then everything shrinks back once digestion ends, usually within one to two weeks. Our article on how long snakes can go without eating explains how this works.

Behavior

Burmese pythons are solitary and mostly nocturnal, though they bask in the sun on cool days. They spend most of their time hidden in thick vegetation, in burrows or partly underwater, which makes them remarkably hard to find even where they are common. In one Florida study, experienced researchers searching a fenced area spotted only a tiny fraction of the pythons known to be there.

Tracking studies in the Everglades have shown that these snakes have a strong homing sense. Pythons moved 21 to 36 km (13 to 22 mi) from where they were caught often headed straight back toward their home area, a navigation ability previously thought to be rare in snakes.

When threatened, a Burmese python usually tries to flee or stay still. If cornered it may hiss and strike. The species has a reputation for being placid, but a large adult is extremely strong.

Reproduction and life cycle

Breeding takes place in early spring, after the cool, dry season. Males find females by scent and court them by rubbing their spurs along the female’s body. A few months later the female lays a clutch, usually of about 12 to 50 leathery eggs, in a sheltered spot such as a hollow, a burrow or a pile of vegetation. Large females lay more: one Florida python found in 2021 contained a record 122 developing eggs.

The mother then does something remarkable for a reptile. She coils tightly around the eggs and stays with them for about two to three months. When the air cools, she makes rhythmic muscle twitches, shivering to produce heat and keep the clutch several degrees warmer than its surroundings. She does not usually eat during this time. Learn how this compares with live-bearing snakes in do all snakes lay eggs?.

Hatchlings cut their way out of the shell with a special egg tooth and are independent at once, receiving no further care. Young pythons grow fast when food is plentiful and can reach breeding size in a few years. Female Burmese pythons in captivity have also produced young without mating, by a form of parthenogenesis, or “virgin birth.”

Lifespan

How long Burmese pythons live in the wild is not well known, because individuals are difficult to follow for many years. In captivity they commonly live 20 to 25 years, and some have lived longer. In Florida, cold snaps are an important cause of death: during severe freezes, such as one in January 2010, a large share of pythons in some study areas died.

Predators and threats

Eggs and young pythons are eaten by many predators, including birds of prey, carnivorous mammals and other snakes. In Florida, bobcats and vultures have been filmed raiding python nests, and alligators both eat pythons and are eaten by them, depending on who is bigger. Once a python passes 3 m (10 ft), it has few natural enemies anywhere.

In Asia, the greatest threats are people. Pythons are collected for their skins, which are used in the leather trade, for meat and traditional medicine, and for the international pet trade. Habitat loss as forests and wetlands are converted to farmland adds to the pressure.

Conservation status

The IUCN Red List classes the Burmese python as Vulnerable, in an assessment published in 2012, because its wild population was estimated to have fallen by at least 30 percent over the previous decade. The species is now common only in a few places, such as parts of Thailand and Hong Kong, and is rare or very rare across much of the rest of its range. International trade is regulated under CITES Appendix II, and the snake is legally protected in several countries, including China, Thailand, Vietnam and Indonesia.

The Burmese python in Florida

The same species that is declining in Asia is thriving in South Florida, where it is an invasive species. Pythons released or escaped from the pet trade established a breeding population in the Everglades that was officially recognized in 2000. Estimates of the current number range from about 30,000 to more than 300,000 snakes, a wide range that shows how hard they are to count.

Their arrival has coincided with steep declines in raccoons, opossums, rabbits and other mid-sized mammals in the southern Everglades. The full story is told in how did Burmese pythons get to Florida?, and our guide to snakes in Florida shows how it fits among the state’s native species. The United States banned imports of Burmese pythons in 2012.

Myths and facts

Myth: pythons crush their prey’s bones. Constriction kills by stopping blood circulation within a few minutes. Bones are rarely broken, and prey is usually swallowed with little visible damage.

Myth: a python’s jaw unhinges. The jaw does not dislocate. The two halves of the lower jaw are joined by a stretchy ligament, and the jaw bones are loosely linked to the skull, which lets the mouth open around very large prey.

Fact: pythons can warm their eggs. Brooding Burmese pythons are among the few reptiles that generate body heat by shivering, a behavior first measured in this species and the closely related Indian python.