Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more.
The expression “so hungry I could eat a horse” might not be just a figure of speech — for the Burmese python, at least.
It had long been thought that the size of the python’s head and body allowed it to devour such enormous prey.
These massive snakes can reach about 18 feet (5.5 meters) in length and weigh up to 200 pounds (90.7 kilograms) — and eyewitnesses have seen them swallowing deer, goats and even alligators.
But it’s not just the size of the python that determines what’s on its menu, revealed a recent study published in the journal Integrative Organismal Biology. What matters more is the size of the python’s “gape” — how widely it can open its mouth.
“One common misunderstanding is that snakes dislocate their jaws to swallow prey,” Bruce Jayne, professor of biological sciences at the University of Cincinnati and lead study author, told CNN Thursday.
“The key thing about snakes is that they have jaws with a great deal of mobility — but no jaws get dislocated.”
Rather than dislocating its jaw before swallowing prey, the python devours animals thanks to a stretchy piece of connective tissue that connects its lower jaw to its skull.
The bone structure at the front of the mouth also helps out.
“The left and right bones are not fused (at the chin). That’s one profound difference between our lower jaws and a snake’s lower jaws,” Jayne said.
The extremely stretchy skin around the jaw allows the python’s mouth to stretch even further around its prey.
And a python’s mouth has one final trick.
“They have additional bones on the roof of their mouth, unlike ours, that have teeth in them,” he added.
Whereas humans have one row of lateral teeth, snakes have both this lateral row — and one that “runs lengthwise,” according to Jayne. These rows of teeth “wiggle back and forth,” dragging prey further toward the stomach.
Impact on wildlife
The scientists examined 43 euthanized Burmese pythons. The team measured their gape using a series of 3D-printed plastic objects of incremental sizes, measuring the widest each snake could stretch its mouth.
The largest probe was 9 inches (22 centimeters) in diameter. Only one snake had a wide enough gape to swallow the object — a python measuring 14 feet (4.3 meters) and weighing 140 pounds (63.3 kilograms).
Unlike cobras, vipers and rattlesnakes, a Burmese python is nonvenomous. It doesn’t kill its prey with its bite, but by suffocation, coiling around the victim and squeezing its muscles tightly to constrict blood flow before swallowing it.
Pythons have recently proved to be a menace for wildlife conservationists in the United States. The Everglades National Park in South Florida once bristled with deer, racoons, possums and foxes. But in recent years, fewer and fewer of these animals have been seen in the area.
The reason? Burmese pythons.
This led to the return this past August of the annual conservation initiative called the Florida Python Challenge, which drew hundreds of professional snake hunters to the Everglades to hunt and kill the nonnative reptiles. The Florida Fish and Wildlife Conservation Commission and the South Florida Water Management District first organized the 10-day event in 2020, with support from nonprofit and private partners.
“The Everglades ecosystem is changing in real time based on one species, the Burmese python,” said study coauthor Ian Bartoszek in a statement in a news release. He is an environmental science project manager for the Conservancy of Southwest Florida.
For more than a decade, officials at Everglades National Park have been researching how to effectively remove the invasive species from this fragile ecosystem, according to the US National Park Service website. A 2012 study referenced by the site suggested that the growing numbers of Burmese python, which likely had initially taken hold when captive snakes from the pet trade were released, could be linked to severe declines in mammal populations in the Everglades habitat.
But the latest study led by Jayne suggests it might not just be smaller mammals at risk due to the overpopulation of pythons — but far larger ones, including deer and alligators.
The researchers questioned whether there is even an upper limit to the gape of some of the very biggest pythons.
“You always have to be careful about extrapolating from your data, but it wouldn’t be surprising to me if a really, really large Burmese python could probably have a gape diameter of about 30 centimeters (11.8 inches),” Jayne said.
Does this mean that if a large python got so hungry it would be able to eat a horse?
“Perhaps they could eat a pony,” Jayne said.