Metamorphosis is a vital part of evolutionary history of amphibians in which their fishlike, gill-breathing larvae turn into lung-breathing terrestrial amphibians. Metamorphosis also means to get the optimum out of both worlds, water and land, which definitely leaves amphibians with an evolutionary advantage.
All amphibians are vertebrates with water-permeable, glandular skin with no scales, feathers or fur. They lay eggs without a protective calcareous shell, the spawn. Larvae hatch from these eggs, which breathe through gills and often look completely different to their parents. Only after metamorphosis do they take on the appearance of the adults and become lung-breathing animals. Therefore, they are easily distinguishable from reptiles, even though newts and lizards look very similar at first glance. But reptiles have dry, scaly skin and no larval state.
No rule without exemption! It is quite certain that the most original strategy among anurans for successful reproduction is the one with eggs deposited in water and tadpoles living in the water until transitioning to land. However, since there is all kinds of threat lurking in water a lot of alternative reproduction strategies have evolved.
Another form of reproduction is the one employed by tropical frogs, like for example the Wallace's Flying Frogs. Here, foam nests, either floating on water or hanging on plants, serve as shelter for deposited eggs. The tadpoles, once ready, will somehow make their way out of the foam or just simply fall into the below water.
The South American Darwin's frogs have a highly unusual method of brooding and rearing their young. After the female frog has left up to forty eggs in the leaves, the male frog would swallow the clutches and store the eggs in a gular pouch where they develop into tadpoles. 3-4 weeks later, when metamorphosis is complete, they hop out as fully formed young froglets.
The spectacular reproduction of Darwin's Frog: The Darwin's frog is one of around 2000 threatened amphibian species of the world. For the whole story of the Darwin's frog project, including pictures of the unique 'birth' of a froglet, feel welcome to visit the Frogs & Friends website.
Exhibition by Frogs & Friends
Exhibition curators: Björn Encke & Annette Kinitz
Text to illustrations: Interactive trip by Frogs & Friends
Art Director: Sebastian Baurmann
Illustration and Animation: Jonas Lieberknecht
Text: Lena Thiele, Heiko Werning
“Wallace’s flying frog” Video Material: Günther Rath
Illustration Darwin’s frog reproduction: Klaus Busse
European tree frog: Emanuele Biggi/Minden Pictures
White-lined leaf frog: Pete Oxford/Minden Pictures
Marsupial frog: Michael&Patricia Fogden/Minden Pictures
Wallace's Flying Frog: Stephen Dalton/Minden Pictures
Surinam toad: David Massinem
Woodfrog on land: Steve Byland
Algae eating tadpoles and tadpole hind legs: Morley Read
Frog on spawn: Matteo photos
With the support of the Interactive Media Foundation gGmbh (IMF)