Greater short-horned lizards have a squat, flat shape and short snouts, which makes them look more like amphibians than reptiles — hence the nickname "horny toads." But these lizards are most famous for their unusual defense mechanism: When threatened, they squirt a stream of blood from their eyes up to a distance of 5 feet (1.5 meters).

The blood is laced with toxic chemicals, which may come from the venomous harvester ants (Pogonomyrmex) that the lizards eat. Although their blood isn’t poisonous, it tastes unpleasant to predators. Short-horned lizards aren't affected by the venom of the harvester ants they feed on because a chemical in their blood plasma neutralizes it. They also produce large amounts of mucus to immobilize the insects, enabling the lizards to swallow them without getting hurt by the venom.