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When python researchers Ian Bartoszek and Ian Easterling tracked a male “scout snake” with a radio transmitter, they expected him to lead them to a big female Burmese python. What they found was much more chilling.
As they pushed their way through the brush of a private property near Naples, Florida, they saw something shocking — a massive 14.8-foot, 115-pound python in the act of consuming a 77-pound, white-tailed deer.
“In the 12 years of doing this tracking effort, this is the most intense thing I’ve ever seen in the field, by far,” Bartoszek said. “Watching an invasive apex predator swallow a full-sized deer in front of you is something that you will never forget. … The impact the Burmese python is having on native wildlife cannot be denied.”
This discovery was disturbing, but it was also thrilling in that it would help Bartoszek and Easterling, who run a python research and removal program for the Conservancy of Southwest Florida, a nonprofit environmental group, understand the full impact these invasive snakes are having on native wildlife.
They arrived when the snake had already half-ingested the deer, and it took another 30 minutes to fully swallow the meal.
Bartoszek’s video and photos show the snake’s relatively small head atop the deer’s rump, but the huge mouth extends around the whole deer, almost like a tight sack. In other photos, the snake resembles a camouflaged body bag.
After watching the snake ingest the deer, the team humanely euthanized it and teamed up with Bruce Jayne, of the University of Cincinnati, to study the Burmese python’s gape, or how wide they can open their mouth.
Their gape determines what they can eat — pythons suffocate prey such as rabbits, bobcats and alligators, then swallow them whole.
Two other snakes were part of the study, including the longest Burmese python ever captured in Florida, a 19-foot behemoth that hunters captured in Big Cypress National Preserve a few years ago.
Burmese pythons, which were brought to Florida via the exotic pet trade in the 1970s and ’80s, have thrived in South Florida wilderness, becoming profoundly destructive to native wildlife. In areas where pythons are prevalent in Everglades National Park, sightings of mammals such as raccoons, opossums and marsh rabbits have dropped by 98%.
Bartoszek and Easterling’s encounter with the deer-eating snake last year, as well as the study, show that larger snakes can graduate to very large prey.
The study showed that these larger snakes have a maximum gape of 10.2 inches. That equates to a circumference of 32 inches. For reference, that’s around the same diameter as the chest of a border collie or Dalmatian.
Knowing the limits on python prey size helps researchers predict the ecological impact the invasive snakes might have as they move into new areas.
Female deer in Florida average around 90 pounds, though they’re a bit smaller in South Florida. Jayne said this particular deer was very near the size limit for the snake’s gape.
“Hence, these snakes resemble overachievers by sometimes testing the limits of what their anatomy allows rather than being slackers that eat only ‘snack-size’ prey.”
The species’ incredible anatomy gives it the ability to gobble sizable animals. Their lower jaw actually splits in half — it’s not fused — and the skin is elastic, allowing for a much wider gape. Burmese pythons can consume prey six times larger than some other snake species of similar size.
No one really knows how often these impressive but destructive invasive species actually take down deer, but biologists now have a better understanding of their capabilities. A 77-pound deer would be ideal prey for an endangered Florida panther, or a human hunter hoping for venison.
Bartoszek, who has performed more than 500 necropsies on invasive pythons, said most of the snakes weighing more than 100 pounds have deer hoofs in their stomachs.
The Conservancy of Southwest Florida started a Burmese python research and removal program in 2013. Their “scout snake” program puts radio trackers on their 120 male snakes during breeding season and lets the males show them where the big, fertile females are.
Removing large females has a more profound impact on the population. The team also accumulates data on behavior and habitat use, which they hope can be used to help slow the python invasion.
The snakes have expanded their range, which started in the southern Everglades and now reaches up to Lake Okeechobee and the outskirts of Fort Myers.
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