By Jonny Lupsha, Wondrium Staff Writer
Reptile jaws have evolved to aid land-based eating. They’re stronger than those of fish and amphibians and reptiles’ tongues help move food around within their mouths. An Austrian man learned this the hard way—in his bathroom.
A 65-year-old man in the city of Graz, Austria, recently had a common fear come true. While he was sitting on the toilet, a five-foot albino reticulated python slithered up the drainage system in the man’s home and bit him in a “sensitive area.” Police believe the python belongs to one of the man’s neighbors and had escaped its owner’s home, somehow making its way through the drains and finding its victim.
Since we here at Wondrium love learning all kinds of nerdy facts about animals, this story led us to look deeper into exactly how snakes and other reptiles have evolved to survive on land. For our research, we revisited the series Zoology: Understanding the Animal World, presented by Dr. Donald E. Moore III, director of the Oregon Zoo.
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In his video series, Dr. Moore states that snake’s jaws adapted to land quite noticeably. “In most reptiles, bony joints allow the snout and upper jaw to move on the rest of the skull,” Dr. Moore said. “The quadrate bone is [the] hindmost part of the upper jaw joint, and can move at both its dorsal and ventral extremes; that is, at both the lower jaw and pterygoid bone, which is part of the palate. Even the snout bones can be raised to open the mouth wide, or lowered to maximize bite force between the jaws.”
According to Dr. Moore, birds and most reptile species have two pairs of temporal openings in their skulls, which is known as “the diapsid condition.” He said that in modern lizards, the lower temporal opening is very large with no lower border, which makes space for expansion of the large jaw muscles lizards use for eating.
“Just as turtles and lizards adapted to herbivorous, omnivorous, and carnivorous lifestyles, all snakes evolved to become carnivores,” Dr. Moore said. “The snakes include non-venomous as well as venomous species, depending on their prey and their ecological niche.
“The common garter snake of North America is a harmless, non-venomous that eats slugs, earthworms, tadpoles, and other small creatures—because of this, it has a relatively small mouth and small teeth that are adapted to manipulating its small prey.”
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Not all snakes eat such small diets. Dr. Moore said that rattlesnakes and pit vipers are venomous and kill rodents for food, which they swallow whole. Likewise, Old World pythons and New World boas, thanks to their large size and ability to disarticulate and rearticulate their jaws, can eat large vertebrate animals like deer.
“The skull of snakes is more mobile than that of lizards due to several movable bones, which enables snakes to swallow much larger prey,” he said. “Although the two halves of the lizard upper jaw—the mandible—are joined by bone, the two halves of the snake’s lower jaw are united by flexible muscle and skin, which allows snakes to spread jawbones widely and allows independent movement of each side.
“Additionally, many snake skull bones are so loosely articulated that the entire skull can flex asymmetrically, and this also helps snakes to swallow their enormous prey whole.”
According to Dr. Moore, snakes slowly swallow prey by moving their recurved teeth over the prey. While one side of the jaws and palate are stabilized by anchoring the teeth into the prey, the other side slowly advances, ratcheting its prey further into the snake’s mouth. This “jaw-walk” takes some time, and snakes still need to breathe while they eat, so its tracheal opening—called the glottis—gets pushed forward between the two sides of the lower jaw.