Honey badgers don't care about snake venom

A black mamba bite packs enough venom to kill a full-grown elephant, but to a honey badger, it's just a mild inconvenience. The snake can pump enough neurotoxin into a honey badger to kill a dozen men, but the badger often survives the encounter. It doesn't have a special immune system that eats the poison. Instead, its body is built like a lock that's been jammed with the wrong key.

Snake neurotoxins usually kill by grabbing onto nicotinic acetylcholine receptors in your muscles. These receptors are supposed to catch signals telling your body to move. When venom plugs them up, the signals can't get through, your diaphragm stops working, and you suffocate.

The honey badger has a specific mutation in its DNA that changed the amino acids at that receptor site. These molecules are bulky and have a different electrical charge than the ones in a human. Because of this structural change, the venom can't actually dock onto the receptor.

It's a physical block rather than a chemical one. Scientists found that these altered binding sites prevent alpha-bungarotoxin, a deadly part of cobra venom, from latching on. The venom molecules just float around because they can't find a place to park.

This shield isn't perfect. A massive dose of venom can still overwhelm the animal, causing it to collapse into a state of transient paralysis. The badger might look dead, but it's actually just waiting for its system to clear the toxins that were unable to bind to its nerves.

The badger isn't the only animal that evolved this specific trick. Mongooses have developed a similar molecular defense through convergent evolution. Even though they aren't closely related, both animals independently changed the shape of their proteins to make snake fangs less effective.

The badger also wears skin that's nearly a quarter-inch thick. It's so tough and loose that even if a snake manages to sink a tooth in, the badger can literally turn around inside its own hide to bite the snake back while the snake is still attached.

Since the venom can't easily shut down their lungs, these animals treat some of the deadliest predators on earth as a snack. But the shield only works against neurotoxins. If a badger faces a snake with hemotoxic venom-the kind that melts tissue and destroys blood-its protein mutation provides no protection at all.