It happens less often than you might think, but when Virginia opossums (Didelphis virginiana) get seriously frightened, they sometimes react by feigning death. Such dramatics are not limited to mammals.
Thanatosis is the animalistic art of playing dead. Much of the time, it's a last-ditch effort to stay alive. Creatures who use this strategy tend to be small and slow-moving. Against a bigger, faster predator, the typical "fight or flight" response doesn't always work. The good news is, predators might not touch an otherwise easy meal if it goes into thanatosis.
Every class of vertebrate animals includes a few species here and there who confuse their attackers by pretending to expire.
Turns out you don't need feet to convince someone you've kicked the bucket. Enter, stage left, a few of the best reptilian actors you'll ever meet: the hognose snakes of North America.
Hognose snakes have facial scales that give them upturned snouts. These are used to push aside dirt, sand and leaf litter as the critters search for food.
North American species belong to the snake genus Heterodon. Other so-named "hognose snakes" dwell in Madagascar and South America. But even though all three groups have upturned noses, they're classified under separate genera by reptile experts.
(FYI: "Genera" is the plural version of "genus." Now you know, and like G.I. Joe says, knowing is half the battle.)
Heterodon snakes occur from the United States' Eastern Seaboard to Arizona and the Rocky Mountains. In the great outdoors, you can find them as far north as central Canada — and as far south as San Luis Potosí, Mexico.
The genus includes three distinct species. Among them, the largest is the eastern hognose (Heterodon platirhinos), which can grow to 46 inches, or 117 centimeters, long. At that size, it's almost twice as big as its little cousin, the southern hognose (Heterodon simus). Rounding out the trio is the charming western or "plains" hognose (Heterodon nasicus).
Gee, aren't those names creative?
Like all snakes, hognoses eat meat. And they're best known for hunting down toads. While the snakes don't constrict, they do inject a mild venom through a pair of large fangs housed near the back of the mouth.
Toads come with their own anti-predator defenses. One technique the amphibians may use involves puffing themselves up to appear bigger.
Some naturalists think hognoses can counter that trick — in a pretty gruesome way. Though this hasn't actually been documented, Heterodon snakes might be using their fangs to puncture the lungs of the toads they consume. A deflated toad is no doubt easier to swallow.
Besides toads, hognoses eat fish, lizards, rodents, salamanders, small birds, eggs and invertebrates (such as earthworms).
The western hognose's dietary habits may change with age. In a 2017 study, researchers tested wild specimens from the Illinois countryside. Chemical data suggested the juvenile snakes were eating a lot of racerunner lizards — along with the eggs those lizards produce. Meanwhile, it seems the adults preferred to gorge themselves on turtle eggs.
Huffing and Puffing
Hognoses lead perilous lives. Hawks, opossums, raccoons and foxes have all been known to make a meal of these reptiles. So will a few other snakes, including the cottonmouth.
When faced with danger, frightened Heterodon snakes put on a little show. Eastern hognoses try to intimidate foes by flattening their necks and rearing up with a threatening hiss. Hence, some people call the reptiles " puff adders."
Unlike real adders, Heterodon snakes don't rely on their venom as a means of self-defense. Remember, hognose fangs are situated towards the back of the mouth. Because of this dental arrangement, the snakes have to more or less chew on the target before any venom can be administered. Since that's not an efficient way to drive off bigger animals, wild hognoses seldom bite their attackers.
But let's get back to the theatrics. When it comes to playing dead, hognose snakes pull out all the stops. You might say they go "whole hog."
A hognose in the throes of thanatosis will writhe around like mad, then go belly-up. The mouth is left open, the tongue dramatically dangling. Sometimes food gets regurgitated in the process, which really revs up the "yuck" factor.
In case barfing's not gross enough for you, picture a snake that just went limp after rolling around in its own feces. Hognoses often poop partway through the faux-death routine. When that happens, the poo tends to ... smear.
Actually, there may be something extra repellant about Heterodon fecal matter. Toads who get eaten by the snakes carry a poison called bufotoxin. Perhaps the scent of hognose poop that's chock-full of this stuff encourages other animals to stay away.
Experts have questions about the death-feigning's true purpose. Clearly, it's an innate behavior in hognose snakes; even scared hatchlings will play dead.
Not all actors show equal dedication, however. One scientist observed a pair of adult eastern hognoses who decided to fake their own deaths — while having sex. Hilariously, the female "broke character" before her partner did and then dragged him behind her for a considerable distance. All the while, the amorous snakes kept right on copulating.
Hognoses are less disposed to playing dead in a captive setting. Easily housed in a 20-gallon (75-liter) terrarium, the snakes can make wonderful pets. Western hognoses are especially popular with keepers and breeders alike.
Again, despite being venomous, Heterodon snakes rarely bite larger creatures, people included. Only on rare occasions do "hoggies" bite the hands that feed them. The venom these reptiles carry isn't considered dangerous to humans — although getting injected with it may lead to blisters, swelling and other symptoms.
Such accidents most often occur when the snake "smells" food on its owner's fingers. You can avoid that problem by washing your hands thoroughly before each interaction.