Burmese python

Identification

The Burmese python is a very large, heavy-bodied snake¹. It has large reddish-brown blotches, outlined in cream or gold, on a pale tan, yellowish-brown or grey background². On top of the head is a clear arrow-shaped mark pointing towards the nose^1,2. Like other members of its genus, it has a dark patch below the eye⁹. Females grow much bigger than males: up to 1.5–1.8 m longer, and the heaviest females weigh nearly twice as much as the heaviest males (85 kg against 44 kg)³.

In the native range, females are thought to mature at about 2.6 m long³. In southern Florida, almost half of the thousands of pythons measured were adults 1.6–2.4 m from snout to vent³. The longest wild Burmese python on record is a 5.79 m female caught in Florida in 2023⁴, and a captive female measured after death was 5.74 m⁵. The heaviest weigh about 97.5 kg³.

Distribution

The Burmese python is native to south-eastern Nepal, north-eastern India, southern Bhutan, Bangladesh, Myanmar, Thailand, Laos, Cambodia, Vietnam and southern China (including Hainan and Hong Kong), and in Indonesia to Java, Bali and Sulawesi¹. Records from Sumatra and Borneo are thought to be mistakes¹. It was long treated as a subspecies of the Indian rock python, Python molurus, and was raised to a full species in 2009^1,10.

It has also been introduced to southern Florida in the United States¹. Pythons were found in the Everglades from 1979, and a breeding population was confirmed around 2000³. Most were probably released or escaped pets². Today pythons live across much of southern Florida, including the Florida Keys, and more than 13,700 had been removed by the end of 2021³.

Habitat

In its native range it lives in grassland, swamps, marshes, rocky foothills, open jungle, woodland and river valleys, and it depends on permanent fresh water². In Florida it lives mainly in the wetlands of the Greater Everglades, and it also uses canals and drainage ditches in built-up areas to move around³.

Behaviour

Burmese pythons are excellent swimmers and often rest partly or fully under water². They are mostly ambush hunters: four wild females tracked in the Everglades spent about 86% of their time resting, often staying put for more than a day³. They can also travel several kilometres and will climb to raid bird nests³. They are sensitive to cold, and below about 10 °C they are increasingly at risk of dying³.

Diet

The Burmese python eats a wide range of animals, mostly mammals and birds, with a few lizards, frogs and snakes recorded in its native range³. It kills prey by constriction³. In Asia, large pythons have eaten leopards, deer, antelope, jackals, porcupines, goats, wild boar and langur monkeys³. In Florida, prey has included American alligators, white-tailed deer, bobcats and threatened wood storks, as well as mice, rats and rabbits³.

Reproduction

The Burmese python lays eggs^2,3. Clutches average about 29–50 eggs and can reach 107². The female coils around her eggs and guards them, and she can shiver to raise their temperature during cool weather^2,3. The eggs hatch about two months after they are laid, and in the native range hatchlings are 48–79 cm long³. There is evidence that females may sometimes reproduce without a male¹.

Venom and medical significance

The Burmese python has no venom³. Like other large pythons it can occasionally attack people⁸, but wild Burmese pythons rarely do. Only one credible report is known of a person killed by a wild Burmese python, an infant in Hong Kong in 1900, and no one has been killed by a wild python in Florida³. The few recorded deaths in Florida were caused by captive pythons³. Most bites happen when people try to catch one, and five unprovoked strikes on biologists in Everglades National Park from 2003 to 2012 caused no serious injury³. Anyone bitten should seek medical care.

Conservation

The Burmese python is listed as Vulnerable on the IUCN Red List (assessed in 2012)⁶. In its native range, people are thought to be its main cause of death, through habitat loss and over-collection³. In Florida, by contrast, it is a damaging invasive species: in Everglades National Park, sightings of raccoons, opossums, rabbits, foxes and deer fell by 85–100% between 2003 and 2011 as pythons spread³.

Similar species

The Indian rock python (Python molurus) lives further west and overlaps with it in Nepal, north-eastern India and Bangladesh^1,10. The two were long treated as one species and are told apart mainly by small scales below the eye¹. The reticulated python (Malayopython reticulatus) is more slender, has a net-like pattern and lacks the dark patch below the eye^1,9. These differences are not a safe basis for handling any snake. Keep your distance from every snake you cannot identify.

In captivity

The Burmese python has been widely kept as a pet, and more than 300,000 were imported into the United States over 30 years². Captive Burmese pythons have lived for 28–34 years³. Released and escaped pets are the likely source of the invasive Florida population², and since 2012 the United States has listed it as injurious wildlife, barring imports without a permit⁷.