Frog life cycle

Tadpole

Frog life cycle

Metamorph

Eggs

Frog

Eggs

Female frogs of most species lay hundreds to thousands of eggs in water, usually attached to aquatic plants or floating in clusters. Fertilisation occurs externally in almost all frog species, with the male releasing sperm over the eggs as they're laid. The embryo develops inside the egg, feeding on its yolk until ready to hatch. Did you know?

• A single frog can lay up to 20,000 eggs at once
• Only a small percentage of eggs survive to adulthood
• Some frog species have parental care, making nests for their eggs from gravel or mud, or guarding them from potential predators.

Metamorph

Metamorphosis transforms the Tadpole into a frog. A transitional stage with both a tail and developing legs. Hind legs emerge first, followed by front legs. The gills are replaced by lungs, and the digestive system typically shifts from plant-based to carnivorous. The tail is gradually reabsorbed as a source of energy. Metamorphs begin venturing onto land while still retaining their tail stub. Did you know?

• The tail is reabsorbed, not shed. It is used as energy
• This stage is one of the most dramatic transformations in the animal kingdom
• Tadpoles can speed up metamorphosis if ponds dry or delay metamorphosis

Tadpole

Most tadpoles hatch from eggs as fully aquatic larvae. They breathe through gills and use a long tail to swim. Tadpole diets vary widely among species. Many graze on algae and biofilms, but others are detritivores (animals that eat dead plants and animals or tiny bits of waste), omnivores (animals that eat both plants and other animals), or even begin hunting other animals from a very early development stage. During this stage, dramatic internal changes are already beginning in preparation for metamorphosis. Did you know?

• They can detect vibrations through a lateral line system
• Some species remain tadpoles for multiple years
• While this is the typical life cycle of a frog, some frog species skip the free-living tadpole stage entirely, developing into small frogs inside eggs.

Adult Frog

Adult frogs are typically at least partially terrestrial, although some species remain almost entirely aquatic. Frogs breathe through lungs and moist skin, which also allows gas exchange. Adults of most frog species are carnivores, feeding largely on insects, small invertebrates using their sticky tongues. When the breeding season arrives, adults of most species return to water, males call to attract mates, and the cycle begins again. Did you know?

• Frogs drink by absorbing water through their skin.
• Some frogs can live over 30 years
• Males of most frog species use vocal sacs to amplify their mating calls

Eggs

Female frogs lay hundreds to thousands of eggs in water, usually in clusters called frogspawn. Each egg is surrounded by a protective jelly coating that swells in water. Fertilisation is external. The male releases sperm over the eggs as they are laid in a process called amplexus. The embryo begins developing inside, feeding on its yolk.

• A single frog can lay up to 20,000 eggs at once
• The jelly coating swells in water to cushion the eggs
• Only a tiny fraction of eggs will survive to adulthood