Frogs and toads have developed some of the most unusual and varied forms of reproduction known among vertebrate animals. The midwife toad drapes fertilized eggs around the hind legs of the male, who returns to the water every night to damp them down. He returns to the water when the eggs are hatched, so the tadpoles emerge safely.
The Surinam toad is even more odd. As the eggs are fertilized, the male presses them onto the female’s back. They sink into her skin and each egg forms a small cell in which the tadpole develops. After 80 days it emerges into the water as a small toad. The eggs and young of the Darwin’s frog, found in South America, are brooded inside the male’s vocal sac. Some frogs lay their eggs in water-filled holes high up in trees in the tropical forest, while others lay them on the damp ground and sit on them to keep the eggs moist.
