Reptiles
Eastern Hognose Snake
Heterodon platirhinos · also called eastern hognose snake, puff adder (US), hissing adder, spreading adder
The eastern hognose snake is the drama queen of North American snakes. Cornered, it does a full impression of a cobra — hood, hiss, and lunging strikes — and if that doesn’t work, it appears to die in front of you, complete with vomiting, a foul smell, and a lolling tongue. It is completely harmless, and it will not actually bite.
Overview
Eastern hognose snakes live in sandy woodlands, fields, dunes, and pine barrens across the eastern and central US. They are diurnal and spend much of their time rooting through loose soil with a sharply upturned snout, digging out toads — their main food. They are stout, variably coloured (grey, brown, orange, olive, sometimes black), and easily mistaken for a viper.
The cobra bluff
Threatened, the hognose flattens its neck into a hood, raises its head, hisses loudly, inflates its body, and makes repeated strikes — almost always with the mouth shut, never biting. The act mimics a large dangerous snake and often works. It has earned the misleading names “puff adder,” “spreading adder,” and “hissing adder.”
Playing dead
If the bluff fails, the hognose thrashes as if dying, voids its bowels and musk, often vomits, then goes limp on its back, mouth open, tongue out, sometimes with blood at the lips, and rolls in the mess to smell like a corpse. Its one flaw: it insists on lying belly-up, and will flip back over if you right it — a giveaway no dead snake would make.
A toad specialist
Toads defend themselves by inflating and by toxic skin. The hognose has beaten both — enlarged rear teeth to deflate a puffed toad, and resistance to bufotoxins. Its mild rear-gland venom helps subdue amphibians and is harmless to people.
Status
The eastern hognose is Least Concern but declining locally with the loss of sandy habitat, road deaths, and killing by people who take the cobra display for the real thing.
Eastern Hognose Snake: common questions
Is the eastern hognose snake dangerous?
No, not to humans in any meaningful way. It does have a mild venom, produced in a gland at the back of the mouth and delivered by enlarged rear teeth (it is technically "rear-fanged"), which it uses to subdue toads and frogs. On the very rare occasions a hognose bites a person — almost always someone handling one for a long time, since the snake will not bite defensively — it can cause localised swelling, itching, and blistering, similar to a strong insect-sting reaction, which resolves without treatment. There is no risk to life or limb. The far bigger danger is to the snake, which is frequently killed by people who see the cobra-like hood-and-hiss display and assume it is venomous.
Why does it pretend to be a cobra?
The eastern hognose has no real weapons against a determined predator, so its first line of defence is intimidation. It draws its head back, spreads the ribs of its neck to flatten it into a broad, hood-like shape, inflates its body with air, hisses loudly, and lunges with dramatic strikes — but it keeps its mouth closed, or barely open, and does not actually bite. The whole performance mimics a large, dangerous snake and is often enough to make a fox, raccoon, or hawk think twice. Because it flattens its neck and hisses, it has picked up local names like "puff adder," "spreading adder," and "hissing adder," none of which are the real puff adder (an African viper).
How convincing is the death-feigning act?
Committed but not clever. If the cobra bluff doesn't work, the hognose escalates to thanatosis (playing dead) — it thrashes violently as though in its death throes, everts its cloaca and releases foul-smelling musk and faeces, frequently vomits up whatever it last ate, and then flips onto its back and lies completely limp with its mouth gaping and tongue hanging out, sometimes with a drop of blood at the mouth. It will often roll in its own mess so it smells like a rotting animal. The catch is that it insists on lying belly-up — if you gently turn a "dead" hognose the right way round, it immediately flips back onto its back, which no genuinely dead snake would do. After a few minutes with no disturbance it lifts its head, checks around, rights itself, and crawls away.
Why is it so specialised on toads?
Toads are abundant, slow, and easy to catch, but they defend themselves in two ways — they inflate their bodies with air to be hard to swallow, and their skin secretes bufotoxins that poison most predators. The eastern hognose has evolved past both. Its enlarged, blade-like rear teeth puncture and deflate an inflated toad as the snake works it back into its throat, and it has physiological resistance to bufotoxins, plus enlarged adrenal glands thought to help it cope with the cardiac effects. This lets the hognose exploit a rich food source that few other snakes can use, and it is why populations decline where toads decline, and why the snake needs the sandy soils that toads (and the hognose's own burrowing snout) require.