Being poisonous has its advantages. It certainly deters predators. And it reduces stress. A poisonous rabbit, rather than sprinting to its destination, could saunter at the speed of a Rough-skinned Newt, the most poisonous salamander on the planet.
One Rough-skinned Newt on the West Coast contained enough poison to kill 25,000 mice. Needless to say, mice are not one of its predators. Only one animal preys on this newt: the Common Garter Snake. Whereas another snake will die if it eats a Rough-skinned Newt, often before the newt dies, the Common Garter Snake merely loses muscle control for a few hours.
The downside, of course, is that a snake that can't move has no control over its body temperature and could potentially overheat. Likewise, the snake can't hide if a Coyote approaches. And eating Rough-skinned Newts makes the snake slower even between meals. Scientists have found that the greater a Common Garter Snake's resistance to the poison in the newt -- and resistance varies from place to place -- the slower it moves, which affords the newt a better chance to escape.
Click here to learn more about the Rough-skinned Newt.
Click here to learn more about the Common Garter Snake.