There are all kinds of ways to get somebody to leave you alone. You can hide and hope they go away. You can take off. You can puff yourself up and make yourself bigger. You can shoot blood out of your eyeballs (well, you probably can’t). For horned lizards like the one in the National Geographic video above, the best strategy is whichever one of these targets a predator's weaknesses.
Horned lizards, also commonly and inaccurately known as horny toads, are funny little beasts. These desert reptiles eat venomous ants, and lots of them, because ants are mostly crunchy shell with little nutritional value. In order to accommodate all those ants, some horned lizards have big bellies.
Those bellies help the lizards get the nutrients they need, but they’re also somewhat of a liability, since a pancake-shaped body is not exactly aerodynamic. "They are short-legged and stubby-bodied," University of Calgary herpetologist Larry Powell told the BBC. "When they run, they give it their best, but they're just not built for speed."
In other words, fleeing is not a great first option. So when a predator approaches, horned lizards perform a simple and instantaneous calculation, first identifying their attacker’s species, then selecting the best way to scare it off.
Lots of animals eat horny toads, or try to. Among the lizards’ foremost predators are snakes, canids like coyotes and dogs, and wild cats. Each snake species hunts differently, which means a different tactic for each. A fast snake can’t be outrun, so the lizards depend on camouflage to hide from them. Ambush predators like rattlesnakes, on the other hand, wait for prey to come to them, and can therefore often be avoided by running like hell on little lizard legs in the other direction. Many snakes try to swallow their prey whole. The lizards’ solution is to make themselves so puffy and big that they won’t even fit in a snake’s mouth.
And then there are the wild dogs and cats. Here’s where all those ant snacks may come in handy. Scientists believe horned lizards borrow chemicals from their venomous food and mix them into their blood. When a large predator gets too close, the lizard lets loose with a face-stream of hot, nasty-tasting, nose-stinging blood. It’s not elegant, but it seems to work; canids and wild cats hate it. And as the would-be lizard-eater paws at its face, the lizard can scoot away.
Image from National Geographic