Burmese Pythons: The Giant Invasive Snake at Risk in Its Native Land

Burmese pythons are nonvenomous constrictors that are among the largest snakes in the world. Growing to huge sizes, the reptiles are a formidable predator capable of eating a huge variety of animals. But while the snakes have become a hugely successful invasive species in Florida, they are facing several threats in their native range.

Where Is the Burmese Python Originally From?

Burmese pythons (Python bivittatus), as the name suggests, are native to Southeast Asia, including parts of India, Nepal, Bhutan, Bangladesh, Myanmar, Thailand, Laos, Cambodia, Vietnam, Malaysia and southern China, according to the Thai National Parks site. These snakes are considered to be semiaquatic and are often found near water or marshy areas, although they can also climb trees. Interestingly, the pythons can even tolerate salt water for prolonged periods of time and have been found swimming in the Gulf of Mexico and Florida's Biscayne Bay, U.S. Geological Survey research ecologists Amy Yackel Adams and Andrea Currylow told Newsweek. While Burmese pythons are native to Southeast Asia, the species was introduced to Florida in the 1970s and 1980s when thousands of the snakes were imported to be sold as exotic pets. Some of these snakes were accidentally or intentionally released and eventually began to breed, establishing a population in the state's southern area, primarily in the Everglades ecosystem. It is virtually impossible to estimate the size of the Burmese python population in Florida because they are well camouflaged and very hard to detect. (The chances of finding one in a small area have been estimated to be less than 1 percent.)

But based on the numbers of Burmese pythons that have been removed from Florida's ecosystems, experts say there are most likely tens of thousands in the state at least. Intriguingly, as the snakes have proliferated in Florida—where they are well adapted to the local environment and face virtually no predators—in its native region, the Burmese python has been listed as "vulnerable" by the International Union for Conservation of Nature. This means the species is likely to become endangered in this region unless circumstances change. In its native region, the python is facing several threats, including habitat degradation, poaching—they are killed for their skins and folk remedies—and capture for the exotic pet trade.

Burmese Python Size—How Big Can They Get?

Burmese pythons can grow to around 20 feet in length, although most specimens are significantly smaller. In South Florida, for example, the average size for those removed from the environment is about 6 to 8 feet, but lengths of up to 19 feet have been recorded. This summer, a 215-pound female python was captured in southwest Florida—the heaviest ever captured in the state. According to Adams and Currylow, this species exhibits "female-biased sexual size dimorphism" in mass and length, meaning the females tend to be larger than the males.

What Does a Burmese Python Eat?

Burmese pythons are nonvenomous, dietary generalists that eat a wide range of birds, mammals and reptiles, killing their prey using constriction. In Florida, these snakes eat more than 70 species of mammals and birds, and they have even been known to eat alligators on occasion. In fact, some native prey populations in Florida have significantly declined because of pythons, Bryan Falk, a program analyst at the National Invasive Species Council, previously told Newsweek. "Pythons are thought to be mostly ambush predators, concealing themselves near pathways used by prey," Adams and Currylow said.

Notably, the python has an amazing bodily response to eating its prey, according to the researchers. "The Burmese python is largely unmatched in the magnitude of its physiological response to ingestion of prey," they said. "Within 48 hours of ingestion, the python undergoes a 40-fold increase in organ growth to digest the intact prey item. After which, the organs—for example, the small intestine, heart and kidney—associated with digesting a meal down-regulate in size."

How Many Eggs Does a Burmese Python Lay?

Female pythons lay large, whitish eggs measuring around 2 by 5 inches, according to Adams and Currylow. "Florida clutch sizes appear to scale with body size, and those found usually contain about 40 eggs," they said. Female pythons brood the eggs, wrapping them within their coils until they are close to hatching, which tends to be July to August in Florida. The females will then "shiver" (contract and relax the muscles along their bodies) to raise the eggs' temperature during the incubation period. The snakes tend to be solitary, and once the hatchlings cut their way out of the egg, the mother no longer provides care. Young pythons are independent and can grow rapidly. The only other time when the snakes tend to be found together is when males and females are mating.