An 8-foot-long lizard that looks like a cross between an iguana and a toad is the giant tuatara. White spikes along its back protrude from olive-colored, pebbly hide. Tuataras have a temperature-sensitive membrane over their eyes which, when lowered, allows the lizards to “see” in total darkness. Tuataras love to hunt small animals at night and sleep during the day. They aggressively attack people who wander too close to their lairs. Although these lizards can be trained to attack, the spines along their backs make them poor mounts. Instinct: Hunt for food

• Grasp in jaws