Regal Horned Lizard - Phrynosoma solare | ©Jason Penney   (Tohono O’odham Indian Reservation, southwest Arizona, US)

Phyrnosoma solare (Phrynosomatidae) are among the larger species of Horned Lizard. Their Latin name is derived from the meaning “rays of the sun” by referring to four large occipital horns at the base of the head continuous with six temporal horns, form a large crown of ten sharp, pointed horns along the base of the head.

American group of Regal Horned lizards have evolved an exceptionally bizarre defense against predators: when under threat they can restrict blood flow from the head until mounting pressure ruptures small blood vessels in and around the eyes, resulting in a spurt of blood that may leap a meter (3 1/2 feet) or more [source].

This bloody mess of a horned lizard (genus Phyrnosoma) isn’t in pain from an attack. Chances are he was feeling extremely threatened, and unleashed a defense mechanism nobody would see coming. The first thing this reptile does when threatened, besides camouflaging anyway, is to stay completely still. If the predator proceeds approach, they’ll alternate between short bursts of running and abruptly stopping to confuse the attacker. If this isn’t successful, they’ll resort to swelling up a bit in size to appear larger and more ‘horned.’ If anything, it just makes them more intimidating and harder to swallow. When all else fails, they shock the threat by spurting blood out of their eyes. It’s a grotesque tactic caused by thin-walled, blood-filled spaces called sinuses found within their eye sockets. In case of emergency, they’ll cause blood pressure in their eyes to rise which, in turn, leads to the sinus walls breaking suddenly. Blood erupts from the eyes in a nicely aimed stream of crimson red, reaching up to 4 feet (1.2 meters). A distasteful chemical combined with multiple bursts of these streams is enough to deter any predator..Or unsuspecting human. A video of this reptile in action can be seen here

Photo credit: randomtruth