A 15-foot Burmese python was caught swallowing a "full-sized" deer in Southwest Florida, proving the invasive apex predators are ambushing and killing bigger prey.
The python was 115 pounds and the deer was 77 pounds, which amounts to 66.9% of the snake's body mass, according to the newly released study "Big Pythons, Big Gape and Big Prey."
"This limbless animal used its body to grip the hind legs of the deer and was forcing it into its body. It was like the python was cork screwing the deer into its mouth," study co-author Ian Bartoszek of the Conservancy of Southwest Florida told McClatchy News in a phone interview.
"It was a jaw-dropping moment seeing this primal scene in the western Everglades. It felt like we caught a serial killer in the act. For us biologists, who have been chasing this animal for a decade, we know what they've been up to, but watching the process? It took a while for our brains to catch up to what we were seeing."
The killing was observed in December 2022 between Naples and Big Cypress National Preserve, and came to light when study co-authors Bartoszek, Dr. Bruce Jayne and Ian Easterling published their findings in the scientific journal Reptiles & Amphibians.
Three pythons, ranging from 15 to 19 feet, were included in the research and all three had a gape -- the maximum size their mouth would open -- of 26 centimeters (10.2 inches) in diameter. That equates to a 32-inch circumference, the study reports.
It's also 40% larger than the previously measured maximum gape for pythons caught in Florida. That means more of Florida's native wildlife are on the menu, the study concludes.
"It's almost a certainty that we have yet to capture the biggest Burmese pythons in Florida," according to Jayne, who is based out of the Department of Biological Science at the University of Cincinnati in Ohio.
"So it seems very plausible that a record-breaking python could have a gape diameter of 30 centimeters and eat a 120-pound deer."
The deer hunter
A romantically inclined male python fitted with a radio transmitter led Bartoszek and a team from the Conservancy of Southwest Florida to the feasting female.
Puncture marks indicate she ambushed the deer with a bite to the neck, then coiled around the buck until it could no longer fight back.
The feeding began head first and the deer was halfway inside the snake when the team arrived, Bartoszek says.
"It was watching us, and when it realized we weren't going to mess with it, the snake kept on swallowing," he says.
"It likely took less than a hour for this animal to capture and consume this deer. As a biologist, it was the most intense thing I've experienced. I was reminded of what we are up against."
It also was the python's last meal.
Once the snake finished, the team forced her to regurgitate, with Bartoszek squeezing it like a tube of toothpaste and Easterling pulling the deer's hooves when they popped out.
This was done so they could collect data from the deer and the snake, and to make it easier to carry the snake to their lab, he said.
"If we had arrived and the deer was still alive, we would have intervened and saved the deer," Bartoszek said. "The deer was clearly dead and we were just waiting for it to play out."
A lot of surprises
It wasn't just the size of the meal that surprised researchers. The ambush happened during the winter, when pythons are believed to have "slowed down," and it was at 10:30 a.m., contradicting a perception of the pythons being primarily nocturnal hunters, officials said.
"It reminds me of how opportunistic they area. We should not underestimate the Burmese python. They will kill and eat animals that are nearly too big to swallow," Bartoszek said.
Pythons are able to stretch their mouths because their lower jawbones are not fused at the front and their skin is elastic, the study reports. That allows them "to consume prey six times larger than similar-sized snakes of some other snake species," the study notes.
"Besides the large absolute size of the deer that was eaten being impressive, our anatomical measurements indicate this deer was very near the size limit on the prey that could be consumed by this snake," Jayne said in an Oct. 24 news release.
"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 conservancy currently has transmitters in 40 male pythons and is using them to find females before they can lay eggs. The females are then captured and humanely euthanized in accordance with state law.
To date, Bartoszek and his team have removed more than 1,000 pythons. If each had eaten at least one deer in their lifetime, that would be more than 13,000 pounds of deer, Jayne estimates.
The large snakes invaded South Florida via the exotic pet trade, and quickly discovered native wildlife is defenseless. Pythons are known to feed on everything from small alligators to bobcats and it's believed they are spreading farther north in the state.
They will also prey on domestic livestock, such as goats and chickens.
"I've been tracking these snakes for 12 years now and I've never felt threatened by a Burmese python or felt one was interested in me," Bartoszek said.
"They are interested in our native wildlife, which has no perspective on this giant snake being a threat. They are completely vulnerable: Babes in the woods with no adaptive strategies to avoid or even know the threat is there."