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This Lizard Shoots Blood Out of Its Eyes to Keep Predators at Bay

We’ve featured some interesting animal defense mechanisms in the past, from moths that camouflage as two flies feasting on bird poop, to caterpillars that mimic snakes, but this horned lizard’s secret weapon is on another level of weirdness.

The regal horned lizard is a small reptile native to Mexico and the southwestern United States. Their main habitat is  the Sonoran Desert Mountains, where they spend most of their time eating harvester ants and other small insects. They can eat up to twenty five hundred ants in one meal, but if you think that’s impressive, you’ll love its most unusual self-defense mechanism – squirting blood out of its eyes.

Photo: Room237/Wikimedia Commons

Life in the Sonoran desert is pretty tough, and the regal horned lizard has its share of predators. From snakes and carnivorous rats, to coyotes and wolves, they all love feasting on the small reptile. Luckily for the protagonist of this article, it has a wide range of self-defense tactics, each specially designed to deal with specific predators.

Observing the regal horned lizard in the wild, scientists observed that it saves its blood-squirting technique for very specific situations. For example, if you were to pick one up and even pretend to harm it, it will probably just sit there and maybe hiss a little. It won’t bite, scratch and it will mot certainly not squirt blood at you. It saves that trick for when it’s most effective.

Photo: Animal Planet/YouTube

Squirting blood at snakes, rats or even humans does little to help the regal horned lizard, but for some reason, it’s very effective against canids and felids, like coyotes and bobcats. The small reptile is able to target where it squirts the blood from its eyes, and it usually waits until its assailant is ready to bite it, so it can shoot straight into its mouth, where it does the most damage. Even though the blood is not poisonous, canids and felids hate it.

“They have an almost violent reaction,” Wade Sherbrooke of the American Museum of Natural History told the BBC. “They shake their heads, they salivate profusely, and try to clear the material out of their mouths.”

 

The blood apparently contains a toxin that binds to receptors in the canid’s mouth, receptors that are not found in human or other species. Sherbrooke claims to have tasted the blood many times, but didn’t detect anything more than a mild acrid aftertaste. Coyotes and bobcats unfortunate enough to get the blood sprayed in their mouths reportedly take up to 15 minutes to recover. By that time the lizard is long gone.

So how does the regal horned lizard shoot blood out of its eyes? A pouch below the lizard’s eyes, the ocular sinus, swells as it fills with blood, and using a sudden surge of pressure, it squirts it out through pores in its lower eyelid in a stream that can travel up to two meters. It can shoot the blood several times if necessary.

 

Sherbrooke claims that regal horned lizards are very good at differentiating between different predators. When threatened by a whip snake, which actively hunts its prey, it will sit still, blending in the background, whereas when running into a rattlesnake, which waits for its prey to get close enough, it will run for its life. Somehow it knows what to do against every type of predators, and even though it doesn’t always escape with its life, this ability to make the right call increases its chances of survival.