Burmese python regurgitates deer during Florida cold snap, study reports

In late November, researchers in Florida’s Big Cypress National Preserve witnessed an unusual, if grisly, moment: a Burmese python regurgitating an entire whitetail deer. The observation, described in Ecology and Evolution, is cited as the first known instance of a free-ranging Burmese python vomiting a deer within the invasive range without direct human disturbance. The event underscored how weather can influence the biology of a cold-blooded predator that has transformed parts of southern Florida since its introduction in the 1970s.

The episode unfolded as a team from the National Park Service and partners were studying the snakes’ feeding habits and their impact on native wildlife. They reported finding a deer carcass nearby the snake and observing the snake with a minimally digested meal after a night when temperatures dipped to about 48.9 degrees Fahrenheit. Researchers noted the python appeared to be swimming in a swamp, a sign that the meal had not fully processed and that digestion had slowed considerably in the chill. The team emphasized that this was not a case of direct human interference and represented a natural, weather-driven response by a large ectotherm.

“Pythons are constantly doing things I never imagined, but this is such a beautiful moment where science and basic principles line up with field observations,” said Mark Sandfoss, senior author of the study and a biologist with the U.S. Geological Survey, in an interview summarized by Live Science. The researchers described the encounter as the first observation of a free-ranging Burmese python vomiting a deer within the invasive range without direct disturbance from humans. The deer remains were found near the snake, illustrating how quickly cold conditions can alter digestion in these predators.

To better understand how deer—one of the larger native prey items—fit into the python’s life cycle, the team conducted a year-long study tracking the digestion of several large female pythons, which are the most likely to consume ungulates. One snake in particular bore a deer gut so large that the meal did not recede over the course of several days. After a night of unusually cold weather, the researchers returned to the area and found the python in a swamp, with the deer remains only partially digested and the midsection not distended, suggesting the meal was expelled as a result of temperature-induced physiological stress.

The finding has nuanced implications for the ongoing fight against the Burmese python invasion. Because pythons are ectothermic, their metabolism and digestion slow dramatically as temperatures fall, slowing prey processing and sometimes triggering regurgitation as a protective mechanism against infection by gut bacteria. In theory, a weather-driven slowdown could reduce the energy the snakes gain from each meal, potentially limiting their reproductive capacity in cooler periods. However, the researchers caution that a surviving snake could simply consume another deer to compensate for the missed meal, potentially sustaining reproduction and further pressuring native wildlife populations.

The discovery arrives amid a broader, intensified effort to control the python population in Florida. State and local agencies have deployed robot rabbit decoys—designed to mimic rabbits’ heat signatures and movement—to lure pythons into detection zones, where biologists can capture or eradicate individuals. The Everglades’ water-management districts have also used similar robotic technologies to monitor and disrupt python hunting. In parallel, incentive programs reward residents for capturing and killing pythons; at least one slayer received $1,000 after removing 87 pythons in a single month.

Experts stress that, despite improving tools and growing experience, the Burmese python problem remains a persistent ecological challenge. A 2023 USGS report characterized southern Florida’s pythons as representing “one of the most intractable” management issues in the world when it comes to invasive species, highlighting the scale of the challenge and the difficulty of eradicating an apex predator that has adapted to a wide range of habitats. The Big Cypress case adds a valuable data point for understanding how climate boundaries may shape the species’ behavior and population dynamics over time.

As researchers continue to document interactions between pythons and native wildlife, including whitetail deer and endangered predators such as the Florida panther, authorities say the fight against the invasive snakes will require sustained, adaptive strategies. The latest observations do not signal an immediate end to the invasion, but they offer a window into how environmental factors can influence the snakes’ feeding cycles and, by extension, their capacity to impact Florida’s native ecosystems. In the meantime, scientists will press on with field studies and collaborative management efforts to monitor python movements, refine control measures, and protect vulnerable species in the state.