A chameleon is endowed with the anatomical equivalent of rearview mirrors. Renowned for its ability to change colors, this lizard possesses something unique to the animal kingdom — both 3-D vision and the ability to see ahead, to the side and behind, with each independently operating eye able to scan a 180-degree arc.

This master hunter, which deploys a lightening-fast tongue that reaches perhaps 1½ times its body length, has the best of both worlds: While one eye looks to the port side for prey, the other can look starboard — or even in its wake — for oncoming predators. And the turret-like eyes do their work while the chameleon's head and body remain stock-still.

But the most innovative eyes may belong to some North American species of horned lizard, small anteaters equipped with gladiator-like armor, which may be picked on by hungry foxes and coyotes. When cornered, this lizard can squirt blood droplets from a sinus beside its eyes, shooting the blood into the mouth of its attacker.

Wade Sherbrooke, a horned lizard specialist who runs the American Museum of Natural History's Southwestern Research Station, writes that the blood "appears to have a repulsive taste to kit foxes and probably to other canids but, as I discovered when I first tried it (the things we do for science!), it was not particularly offensive to my taste buds."