The Life Cycle of a Frog

It includes three stages: Egg, larva, and adult

By

Updated on August 31, 2024

The life cycle of a frog consists of three stages: egg, larva, and adult. As the frog grows, it moves through these stages in a process known as metamorphosis. Frogs are not the only animals that undergo metamorphosis; most other amphibians also experience remarkable changes throughout their life cycles, as do many species of invertebrates. During metamorphosis, two hormones—prolactin and thyroxine—control the transformation from egg to larva to adult.

01

of 04

Breeding

Close-up of frogs mating on a banana leaf — Riza Arif Pratama / EyeEm / Getty Images

The breeding season for frogs usually occurs during the spring in temperate climates and during the rainy season in tropical climates. When male frogs are ready to breed, they often use loud croaking calls to attract partners. Males produce these calls by filling a vocal sac with air and moving the air back and forth to create a chirp-like sound.

When mating, the male frog holds onto the female's back, clasping his front legs around her waist or neck. This embrace is referred to as amplexus; its purpose is to ensure that the male is in the optimal position to fertilize the female's eggs as she lays them.

02

of 04

Stage 1: Egg

Frog surrounded by eggs — Peter Garner / EyeEm / Getty Images

Many species lay their eggs in calm water among vegetation, where the eggs develop relatively safely. The female frog lays numerous eggs in masses that tend to clump together in groupings known as spawn. As she deposits the eggs, the male releases sperm and fertilizes them.

In many species of frogs, the adults do not stick around to provide further care for their eggs. But in a few, parents remain with the eggs to look after them as they develop. As the fertilized eggs mature, the yolk in each egg splits into more and more cells and begins to take the form of a tadpole, the larva of a frog. Within one to three weeks, the egg is ready to hatch, and a tiny tadpole breaks free.

03

of 04

Stage 2: Tadpole (Larva)

Tadpoles have rudimentary gills, a mouth, and a long tail. They barely move for the first week or two after hatching, and during this time, they absorb the remaining yolk left over from the egg, which provides much-needed nourishment. After absorbing the yolk, the tadpole is strong enough to swim.

Most tadpoles feed on algae and other vegetation, so they are considered herbivores. They filter material from the water as they swim or they tear away bits of plant material. As the tadpole continues to grow, it begins to develop hind limbs. Its body elongates and its diet grows more robust, shifting to larger plant matter and insects. Later in development, the tadpole's front limbs grow and its tail shrinks. Skin forms over the tadpole's gills.

04

of 04

Stage 3: Adult

At approximately 12 weeks, the tadpole's gills and tail are fully absorbed into the body, meaning the frog has reached the adult stage of its life cycle. It is now ready to venture out onto dry land and, in time, repeat the life cycle.