The Adder that Tells Time
Australia has many unique creatures that people find fascinating. One example is the floodplain death adder and its habit of eating dangerous frogs.
The marbled frog has a defense that could get the adder into trouble. It secretes an incredibly sticky mucus. If the adder gets some of this on himself, dirt, leaves and even sticks will begin to stick to him. When the adder strikes a marbled frog, he immediately drops the frog and waits. Studies show that two thirds of the stickiness of the mucus has degenerated by ten minutes after the frog dies. And that's how long the adder waits before he consumes the frog unharmed.
The Dahl's frog produces a powerful poison for its defense. The adder will quickly strike the frog and drop it so the adder's poison can kill it. Apparently, even this momentary contact is enough to deliver some poison to the adder. Scientists report that after such a strike the adder will writhe about. Eventually it recovers and continues to wait. After an average of 42 minutes, the adder eats the frog. Research shows that by this time the poison has degraded to nontoxic levels.
Researchers debate whether the adder's strategy of waiting different times for differing frog defenses is learned or inherited. We can be sure, however, that it was created.