大象传媒

David Attenborough looks at a South American red-eyed tree frog, whose colouring is a close match for the tree on which it sits. The eggs aren't very conspicuous either as they are just little blobs in transparent jelly - but they are always laid on leaves overhanging water. The eggs develop very quickly in the jelly and in less than a weak they are recognisable tadpoles and almost ready for freedom. Then the jelly liquefies and the tadpoles simply drop into the water below. But that's only if they are the lucky ones. Wasps raid the cluster and steal some of the tadpoles to feed their young. And yet the tadpoles aren't entirely helpless. By the time they are five days old they know when they are under attack and they can do something about it. They can wriggle free of the eggs and the leaf and deliberately drop into the water below, raising the alarm for all the other tadpoles to do the same. Once in the water, they may be under-developed but they can swim well enough to hide among the plants.