When the regal horned lizard feels threatened, it deploys a disgusting defense—shooting streams of blood from its eyes! The behavior doesn’t hurt the animal, but it does help scare away predators that are out to eat it. Several members of its genus, Phyrnosoma, also use this unique adaptation to improve their chances of survival.
Regal horned lizards live only in the Sonoran Desert in Northern Mexico and the Southwestern U.S. They have extremely flat bodies, have brown coloring, and are covered with horns and spikes. These features help camouflage the lizards so they blend in with their drab, rocky surroundings. “They don’t run away from danger like most lizards if spotted by predators, like foxes or coyotes,” says Brian Sullivan. He’s a herpetologist who studies regal horned lizards at Arizona State University.
When approached by a predator, the lizard goes into emergency mode. It turns its head toward the advancing threat. Then the sinuses around the regal horned lizard’s eyes begin to fill with blood. Pressure builds within these hollow cavities in the animal’s face until—BAM! The blood breaks through a tiny blood vessel, called a capillary, in the lizard’s eye. A fountain of blood erupts, squirting several feet—hopefully, right into the predator’s mouth. Since regal horned lizards dine primarily on venomous seed harvester ants, their blood tastes terrible. That and the shock of being hit in the face with blood usually causes the would-be attacker to run away in horror.