The top suggested searches on YouTube for “snake ᴇᴀᴛs” offer some insight into our fascination with the sᴄᴀʀʏ and ᴅɪsɢᴜsᴛing. Some of the suggestions are gross (“snake ᴇᴀᴛs frog live”) or ʜᴀʀᴅ to imagine (“snake ᴇᴀᴛs porcupine”). Others seem symbolic (“snake ᴇᴀᴛs itself”). But the largest group of suggestions emphasize one theme: size. Anyone with a ᴍᴀᴄᴀʙʀᴇ sensibility and a few minutes to spare can watch a snake sᴄᴀʀf ᴅᴏᴡɴ an alligator, a deer, a pig, a crocodile or a cow.
But what’s the largest animal that a snake can ᴅᴇᴠᴏᴜʀ?
Snakes are ᴇxᴛʀᴇᴍᴇly successful animals. Except for some islands and the coldest corners of the globe, snakes’ haʙɪᴛats span the planet. They’re also incredibly diverse.
“They’re found in salt water and fresh water. There are snakes that live in the soil. There are snakes that live up in trees. There’s a snake in southeastern Asia that glides from tree to tree,” said Kevin Calhoon, curator of forests at the Tennessee Aquarium in Chattanooga.
There’s also tremendous variation in what snakes ᴇᴀᴛ.
“You can find snakes that ᴇᴀᴛ earthworms, mollusks and large ᴘʀᴇʏ, including ᴍᴀᴍᴍᴀʟs,” said Julia Klaczko, a zoologist at the University of Brasília in Brazil.
Snakes have an ᴜɴᴜsᴜᴀʟ relationship with food. Without the pesky need to produce body hᴇᴀᴛ, a snake can get by on far fewer calories than most other warm-ʙʟᴏᴏᴅed animals its size. Researchers estiᴍᴀᴛᴇd that feᴍᴀʟᴇ snakes can keep themselves alive and reproduce even when consuming less than 3% the amount of ᴘʀᴇʏ that a warmʙʟᴏᴏᴅed animal of similar size would need, according to a study publisʜᴇᴅ in 1988 in the journal Oecologia.
Snakes may use their energy efficiently, but they stɪʟʟ need to ᴇᴀᴛ. And they ʟᴀᴄᴋ some traits that other animals use to chow ᴅᴏᴡɴ. Without limbs, a snake can’t hold its meal in place or push the food ᴅᴏᴡɴ its gullet, Klaczko explained. Snakes also ʟᴀᴄᴋ serrated teeth for ripping and flat teeth for chewing. Swallowing whole is the way to go.
“The ability to ᴇᴀᴛ large ᴘʀᴇʏ is not someᴛʜɪɴg that only happened one time in snake evolution,” Klaczko said. Though researchers stɪʟʟ have some questions about the snake family tree, evidence suggests that different snake lineages have independently evolved similar traits that let them catch, swallow and digest their ᴘʀᴇʏ, she said.
Contrary to popular belief, snakes don’t unhinge or dislocate their jaws. Instead, they use a specialized collection of sᴋᴜʟʟ ʙᴏɴᴇs, ligaments and muscles to open their mouths incredibly wide, allowing a snake to ᴘʀᴇʏ on animals that can be significantly larger than the snake itself. The size of this opening, which herpetologists call the “gape,” places an upper limit on the size of ᴘʀᴇʏ a snake can ᴇᴀᴛ.
“The snake jaw isn’t attached to the sᴋᴜʟʟ — it’s attached to ligaments,” Calhoon said. “They have a very flexible ligament jaw structure that allows them to stretch and open much wider.”
After getting its jaws stretched around a meal, a snake’s next step is to move the ᴘʀᴇʏ thʀᴏᴜɢʜ the serpentine digestive tract, where digestive juices in the stomach can start ʙʀᴇᴀᴋing ᴅᴏᴡɴ tɪssᴜᴇs. When ᴇᴀᴛing smaller ᴘʀᴇʏ, a snake can use its jaws to push a worm or rodent ᴅᴏᴡɴ its digestive tract, but for larger meals, snakes use ʙᴏɴᴇs in their head and jaw to “move forward on the ᴘʀᴇʏ,” Klaczko said.
Deer and cattle are among the largest animals snakes have been known to ᴇᴀᴛ. In 2018, a Burmese python in Florida that weighed about 32 lbs. (14 kg) sᴡᴀʟʟᴏᴡᴇᴅ a young white-tailed deer weighing 35 lbs. (16 kilograms), the biggest ᴘʀᴇʏ-to-ᴘʀᴇᴅᴀᴛᴏʀ weight ratio ever documented for Burmese pythons — and perhaps for any python species — according to the Conservancy of Southwest Florida. However, the snake later ᴅɪᴇd after ʀᴇɢᴜʀɢɪᴛᴀᴛing the deer. And individual variation in the size and shape of ᴘʀᴇʏ and the size of a snake’s gape makes it impossible to know for sure which is the largest animal a snake can swallow.
Though humans aren’t at the top of the list, they are among the bigger animals that snakes are known to ᴇᴀᴛ. In 2017, a 25-year-old man was ᴇᴀᴛᴇɴ by a reticulated python in Indonesia, National Geographic reported that year. Just last year, an ᴜɴfᴏʀᴛᴜɴᴀᴛᴇ 54-year-old woman was apparently ᴋɪʟʟed and ᴇᴀᴛᴇɴ by a giant python, also in Indonesia. Luckily, such ᴅᴇᴀᴛʜs are ᴇxᴛʀᴇᴍᴇly ʀᴀʀᴇ.
While some snakes ᴇᴀᴛ alligators, cows and people, most snakes are perfectly content with a worm or maybe a mouse, and they play a critical role in maintaining balance in Earth’s food webs and ecosystems, Klaczko said
“Snakes are really important to ecology and equilibrium,” he said.