The Horny Lizard (Phrynosoma)
The Horny Lizard is an unusual lizard found only in the arid desert areas of the Western United States and Northern Mexico.  Its name derived from its strange appearance, the horny lizard can also go by the aliases horned lizard, horny toad, or horned toad. The Horny Lizard has a curious resemblance to a toad, as it has a wide, flat, squat body with a short, broad-based tail, rather than the characteristic long, sleek, tubular bodies of most lizards. It also has a fearsome dragon-like appearance, as its back is covered with small conical spines, its sides are fringed with longer spines, and its head is "crowned" with a row of horns. 
Despite its fearsome appearance, the horny lizard is as laid-back as most other lizards, spending a large portion of its time basking in the sun. It spends its nights burrowed in the sand and hibernates throughout the cold months of autumn and winter. It feeds on a diet composed mainly of ants and other slow-moving, ground-dwelling insects such as spiders, ticks, sow bugs, beetles, termites, and grasshoppers. 
However, the horny lizard is not at the top of the food chain in its desert habitat, and must also be on the alert for predators. Horny lizards are preyed upon by hawks, roadrunners, snakes, coyotes, ground squirrels, cats, and dogs.  To combat these predators, the Horny Lizard has developed a number of remarkable defenses. Its primary defense is its extraordinary camouflaging abilities. However, when its ability to remain unseen fails, it puffs itself up, thrashes its horns about, and can even squirt blood from its eyeballs!  The remainder of this website will focus on these unique defense mechanisms, especially:
Ontogeny: When and how these defense mechanisms develop over the course of the lizard's life.
Phylogeny: Evolutionary relationships between different species of the Horned Lizards.
Mechanism: How these defense mechanisms physically function.
Adaptation: The adaptive benefits of these defense mechanisms.
Over the years, the Horny Lizard has become a beloved part of the wildlife of the Southwest and a source of pride amongst Southwestern people, especially students of Texas Christian University, where it is the mascot. Despite its fearsome appearance, the Horned Lizard is quite friendly. It is said that, assuming you manage to catch one and elude its defensive mechanisms, you can lull it to sleep in your hand by turning it upside down and stroking its soft underbelly!  Unfortunately, its intimidating outer appearance, combined with its friendly nature, has led to its popularity as a household pet. Populations of Horny Lizards have decreased dangerously as a result of people capturing these fascinating creatures as pets. Because of their demanding diet, based primarily on specific species of ants, most lizards quickly die in captivity. Some species are now endangered and are protected under laws which will help to ensure the survival of these intriguing creatures.