Cry Me A River…. Of Blood?


The Horned Lizard (Phyrnosoma) is a very interesting creature, with a very unique defensive strategy!  It is neither a toad, nor a frog, though often called a “horned toad/frog” due to it’s stout body.  This horned lizard is covered in modified scales which are now spiny-like.  The horns on their head, however, are composed of bone, and are not derived from the scales.

These are commonly found in North America, or parts of the United States, or even in the deserts of Mexico.  They do look similar to their relatives the Australian  thorny devil.  They both are sit-and-wait predators, their diet consisting mostly of ants.  However, one of the unique differences of these Horned Lizards in Texas, is they have a very interesting defensive mechanism! Blood.


Though these lizards are capable of a wide range of predation avoidance, their most interesting one they have adapted to do,  is to literally bleed from their eyes!!!  At first threat, their instinct is to remain still and camouflage within the environment.  If the predator spots them, their next step is to run and stop in short burst, purposely trying to confuse their predator. They puff up as large as they can, trying to look unappetizing, and possibly too bulky to eat.  But the last straw, for four of the species of Horned Lizards, they are able to literally squirt blood from the corners of their eyes of a distance up to 5 feet!!

This is possible as they restrict the blood flow that leaves the head, which increases pressure on the vessels around the eyelids.  But why do this?  Well first of all, this a extremely confusing to the predator, but the blood is actually found to be foul tasting for canine and felines, reducing their predators immensly.  So watch out you feline predators, this lizard will cry you a river of rotten tasting blood!

Simply sublime.  Who thinks of these adaptations!?  Evolution is truly amazing.