Burmese pythons are not only large snakes, growing to over 18 feet and 200 pounds, but they are large eaters, taking prey as large as deer.
Biologists at the University of Cincinnati have found that it’s not just the size of its head and body that puts just about everything on the snake’s list. They have developed highly stretched skin between their lower jaws which allows them to consume prey six times larger than snakes of similar size.
The study, funded in part by a grant from the National Science Foundation, was published in the journal integrative biology.
Since most snakes swallow their prey whole, they must have wide mouths to accommodate the meal. Unlike the mandible, the mandible bones of snakes are not connected, which allows them to open wide.
“The elastic skin between the right and left mandibles is drastically different in snakes. Just over 40% of their total yawning area is on average from the stretched skin,” said lead author and UCLA biology professor Bruce Jayne. “Even after correcting their big heads, their gaps are enormous.”
Snakes are limitations. They bite their prey and wrap their powerful coils around it, fatally cutting off the animal’s vital blood flow, before they eat it entirely at their leisure.
The larger the prey, the more energy the snake derives from the meal. For snakes, this means not having to hunt as much, which can carry significant risks in a world filled with busy roads and dangerous predators.
Together with snakes, Jain studied the size of the hiatus of brown tree snakes, a rather venomous tree specialist who hunts birds and other animals in the forest canopy. Brown tree snakes were introduced in the 1950s to Guam, wiping out many bird species.
Besides measuring snakes, Jayne also measured the dimensions and weight of potential prey animals. This allowed Jayne to use the snake’s size to predict the maximum size of its prey and the relative benefits of consuming different species such as alligators, chickens, rats or deer.
The study found that smaller snakes derive greater benefits in relative prey mass from a modest increase in yawn volume. This gives young snakes an early advantage in catching a wider range of prey compared to other snakes of their size, Jane said.
The large size also helps snakes avoid becoming foragers. Snakes fall prey to everything from wading birds to mink and raccoons to alligators and other snakes.
“Once those snakes got to a reasonable size, the crocodile could just eat them,” Jane said. “The snakes eat the crocodile.”
Like the invasive brown tree snakes on Guam, Burmese pythons wreak havoc on the environment in Everglades National Park where they were introduced due to the release of captive animals from the exotic pet trade in the 1980s.
Study co-author Ian Bartoshek is an environmental science project manager at the Conservancy of Southwest Florida, where he led a snake-tracking project. They implant radio transmitters in male snakes during the breeding season to find females before they can lay more eggs. A large female snake can lay more than 100 eggs.
Researchers routinely find deer hooves and the remains of other large animals in their stomachs. Bartoszek depicted a single snake vomiting a whole white-tailed deer.
“The Everglades ecosystem changes in real time based on one species, the Burmese python,” Bartoszek said.
The good news is that snakes rarely attack people. Bartoszek said the only defensive encounters he had with wild snakes were with females guarding their nests.
“Driving there is more dangerous than working with snakes,” he said.