Burmese python

Burmese python, (Python bivittatus), species of constrictor snake that is native to various environments in southern and Southeast Asia, including several islands in Indonesia, and is known for its exceptional size and its environmental adaptability. Burmese pythons inhabit mangrove forests, rainforests, swamps, grasslands, rivers, and rocky areas, in a range extending from Nepal, Bangladesh, northeastern India, and Myanmar (Burma) eastward to southern China and southward to Vietnam, Laos, Cambodia, and Thailand north of the Isthmus of Kra, as well as the islands of Java, Bali, Sumbawa, and Sulawesi. In addition, the Burmese python has established populations in southern Florida, where it is considered to be an invasive species. It was classified as a subspecies of the Indian python (Python molarus) until 2009.

Natural history

Burmese pythons are among the longest snakes in the world. Adults tend to grow to between 3 and 5 meters (10 and 16 feet) in length and can weigh as much as 90.7 kg (200 pounds). The largest confirmed specimens have been measured at 5.8 meters (19 feet) long and 97.5 kg (215 pounds), but there are unconfirmed reports of 7-meter- (23-foot-) long individuals. The skin of an adult Burmese python has large dark brown patches set against a cream or dark tan background. Such cryptic coloration also occurs in juveniles, but they display a sharper separation between one color and the next.

Burmese pythons are apex predators that consume a wide variety of prey. Although they prefer small mammals (such as rodents, rabbits, and raccoons), they also eat larger prey—including large mammals (such as deer, pigs, and goats), other large reptiles (such as alligators), and domesticated birds (such as poultry). The Burmese python captures its quarry by waiting motionless until the prey is close enough for the snake to strike and hold with its powerful jaws. It then coils its body around the victim and suffocates it before consuming it whole. There are several reports of the snake attacking people, but such encounters have been rare, being limited largely to captive snakes that were provoked.

The species reproduces both sexually and through parthenogenesis (that is, a reproductive strategy that involves development of a gamete [sex cell] without fertilization). Mating—which may include one or more males breeding with a single female—occurs between December and March in mainland Asia, insular Indonesia, and southern Florida. A female deposits a clutch of eggs (which typically number fewer than 40 but in larger snakes can number as many as 80 to 100) between March and June. She incubates the clutch until hatchlings emerge some two months later. Most young Burmese pythons reach sexual maturity by age 2 or 3, males becoming sexually mature at an earlier age than females. Ecologists note that Burmese pythons can live for more than 20 years in the wild and up to 25 years in captivity.

Invasive species

It is not certain how Burmese pythons became established in southern Florida. They were first brought to the U.S. as exotic pets, starting during the 1980s, and it is likely that when they grew too large to manage, some snake owners released them into the wild. Since these snakes cannot survive freezing or near-freezing temperatures, only those set free in southern Florida, where temperatures remain above freezing year-round, survived. Additional snakes were emancipated after Hurricane Andrew cut across southern Florida in 1992 and destroyed a reptile warehouse near Homestead.

By 2000 the snake had established breeding populations, and by 2010 it was challenging the American alligator (Alligator mississippiensis) for dominance of southern Florida’s wetlands. (There is evidence that the snake and the alligator prey on each other.) By 2012 Burmese pythons had become significant predators in the area, reducing deer, bobcat, raccoon, and opossum populations in the Everglades by 87 percent or more while effectively wiping out foxes and rabbits in the area.

Conservation status

The International Union for Conservation of Nature and Natural Resources (IUCN) lists the Burmese python as a vulnerable species. The snake’s wide distribution in mainland Southeast Asia and Indonesia and the establishment of a population numbering at least several tens of thousands in the Everglades and other parts of southern Florida conceal severe population crashes of up to 80 percent in a single decade in some parts of its native geographic range. Ecologists note that Burmese python numbers have fallen throughout the early 21st century, because people in several countries harvest the snake for food, its hide, which is used to make leather garments and drums, and the pet trade. (By some estimates, more than 300,000 individuals have been exported to the U.S. since 1980.) Burmese pythons are also threatened by habitat loss, specifically the conversion of forest and marshland to agricultural land, a process that reduces prey populations and the snake’s ability to hide from hunters. The species is part of zoo collections around the world.