When threatened or molested by other animals, such as dogs, coyotes or foxes, certain horned lizards (''Phrynosoma cornutum, P. coronatum and P. solare'') will respond by squirting a spectacular amount of blood from their eyes. They accomplish this by constricting venous outflow from the head which increases blood pressure and causes leakage from the ocular venous sinuses. | When threatened or molested by other animals, such as dogs, coyotes or foxes, certain horned lizards (''Phrynosoma cornutum, P. coronatum and P. solare'') will respond by squirting a spectacular amount of blood from their eyes. They accomplish this by constricting venous outflow from the head which increases blood pressure and causes leakage from the ocular venous sinuses. |