Burmese pythons can swallow their prey whole (Credit: US Gov/ Public domain/ Flickr)

Burmese pythons are voracious eaters. The mighty predators — which reach over 18 feet in length and 200 pounds (90.7 kg) in weight — can swallow prey as large as a deer. Researchers previously believed that the reptiles' massive heads and bodies allowed them to achieve this incredible feat. Now, a new study asserts it is the size of the python's "gape" — how wide it can open its mouth — that determines the size of animal it can swallow.

University of Cincinnati Professor Bruce Jayne and his team reached this conclusion after examining 43 dead pythons. The invasive snakes were euthanized to help reduce their population in the Florida Everglades.

One python could swallow a nine-inch diameter object (Credit: Bruce Jayne)

The researchers began by creating 3D-printed plastic objects, or probes, of varying sizes. The largest one measured nine inches (23 centimeters) in diameter. They then used the probes to measure each snake's "gape." Only one python — a 130-pound (59 kg) 14-foot (4.3 m) long specimen — could open its mouth wide enough to swallow the nine-inch diameter object.

"The probe is big enough to fit over my head," Jayne said. "To give you an idea of how big that specimen was, it's too large to fit inside a 5-gallon [20 liters] bucket. That was a hefty one."

CT scans of the Burmese pythons' elasticized jaws (Credit: Jayne et al., Integrative Organismal Biology, 2022)

The scientists state that unlike the human jaw, which is directly attached to the braincase, snakes have flexible tissue linking their lower jaws to their braincase. This enables the reptiles to open their mouths wider. However, the Burmese pythons have taken this ability further. They have evolved extremely elastic skin in their lower jaws. This allows them to swallow prey up to six times larger than similarly sized snakes.

"The stretchy skin between left and right lower jaws is radically different in pythons. Just over 40 percent of their total gape area on average is from stretchy skin," Jayne says. "Even after you correct for their large heads, their gape is enormous."

The team hopes their findings will help officials better recognize the damage the pythons can cause to Florida's ecosystem. "It's not going to help to control them," Jayne says. "But it can help us understand the impact of invasive species. If you know how big the snakes get and how long it takes for them to get that size, you can place a rough upper limit on what resources the snake could be expected to exploit."

Resources: livescience.com, UC.edu, cnn.com