The frog life cycle is fascinating! Most frogs reproduce in similar ways with four main stages of development called metamorphosis. Frogs transform from egg, to tadpole, to forget, to adult frog over a period of a few weeks to a few years depending on the species and climate.
The frog life cycle consists of 4 main stages: 1. Egg, 2. Tadpole, 3. Froglet, 4. Adult Frog. The evolution through these stages is called metamorphosis and complete transformation can take up to 28 weeks depending on species and climate.
Most sites that cover the frog life cycle are not specifically about frogs, that is where we stand out! Many of the most popular videos on YouTube about the frog life cycle are about exceptions, not how most frogs transform. These exceptions often confuse learners. Let us clear things up for you! 🙂
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This entire site is dedicated to frogs so we have many resources to help you better understand frog reproduction and their life cycle. Let’s start with how most frogs transform from egg to adult frog.
The following table is a summary of the frog life cycle stages with the average duration of each stage (which varies depending on species and climate), as well as the scientific or common names for each step:
|1. Egg||Embryo||1 to 3 days|
|2. Tadpole||Polliwog||14 to 16 weeks|
|3. Froglet||Young Frog||6 to 9 weeks|
|4. Adult Frog||Frog||2 to 4 years|
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As a general rule, a frog eggs are embryos laid by a female frogs simultaneously fertilized by a male frog during reproduction. The resulting zygote goes through cell division and embryonic development to later transform into a tadpole.
During reproduction, female frogs can lay 2 to 20,000 eggs depending on the species and the climate. In seasonal climates, frogs generally reproduce once in the Spring, though some species may reproduce twice during Spring and Summer. In tropical rainforests, frogs generally reproduce at any time of year since the climate is temperate.
While being laid, frog eggs absorb water around them to form a jelly. This allows the eggs to cluster together and grow in size. This jelly enclosure allows eggs to stick to vegetation that anchors them down to avoid floating away. Most frogs reproduce calm freshwater to increase the chances of survival. The jelly also enlarges the eggs making them too big for certain predators while protecting them from bacteria.
During this stage, the frog feeds off of its yolk supply while its internal organs begin to form along with its gills. The transformation to a tadpole is initiated by the Thyroid hormone and generally takes only a few days (2 to 3) for frog eggs to transform into tadpoles. Frogs lay eggs in clusters whereas toads lay eggs in strings.
Tadpoles, also called polliwogs, are the aquatic larval stage of frogs that evolved from eggs after 3 to 25 days. They measure about 40-45mm and live in water. Tadpoles evolve for 14 to 16 weeks depending on the species and the climate in which they live.
At the very beginning of this stage (no feet), tadpoles are herbivores, they eat the vegetation around them, breathe through their skin and feed on the remaining yolk of their egg that is located in their gut while their gills, tails, and bodies still develop.
At the middle of this stage (with feet), tadpoles have short, oval bodies, with long wide tails, tiny mouths, and breathe through their external gills, and eventually through their internal gills once they have developed. At this stage, tadpoles begin to also feed on animal matter (omnivores) and may swim around in schools like fish.
At the end of the tadpole stage, the frog’s hind and front legs begin to grow, the tail starts to disappear through the process of apoptosis, or programmed cell death. For those wondering, the tail does not fall of, it absorbs into the body 😉 Tadpoles require water, food and shelter to survive as they are vulnerable to many land and water dwelling predators. Late tadpoles begin to develop lungs allowing them to breathe on land (CTNF).
A froglet is a tadpole that completed the last stage of metamorphosis and is now a young frog. Froglets have legs, lungs, and a tail that will eventually disappear through the process of apoptosis.
Froglets can live outside of water, may still have part of their tail or a nub, and generally look like a smaller version of an adult frog.
At this stage, the frog can leave the water and live on land for short periods of time. Contrary to toads, the frog will still need to remain close to bodies of water to survive, but it can hop around and swim away from predators using its growing legs.
A froglet will slowly lose its tail and grow larger with time. It can eat bugs and other invertebrates. Depending on the species and the stage of development, froglets could also start to eat small rodents.
Froglets have generally completed their metamorphosis into adult frogs once they can reproduce. This can take a few years depending on the species.
4. Adult Frog
The last life cycle stage for frogs is adult and at this stage the frog can reproduce to restart the cycle. Adult frogs no longer have their tail, can live on land, can breathe through lungs, and are obligate carnivores.
Adult frogs only feed on live animal-based food and have higher chances of survival compared to tadpoles. Adult frogs have much more advanced and sophisticated defense mechanisms making them much less vulnerable to predators compared to frogs in other stages in their life cycle.
Once mating season comes along, adult frogs will head to an adapted location with freshwater and males will call females to attract them to their location. Each frog species has a unique call they use to attract frogs of the same species.
And it is at that location that the frog life cycle starts over again! 🙂
Here is the complete frog life cycle with images of real frogs. The quality is amazing it is really interesting to see the detail of what a tadpole looks like with a high quality photo. But not all frogs reproduce following this exact life cycle! We explain more below.
Exceptions to The Frog Life Cycle
Most frog life cycles are as described above. Frogs lay thousands of eggs, knowing they are very vulnerable to predators and count on high egg counts for survival. However, some frogs have different, yet incredibly fascinating ways they lay and hatch their eggs.
African Bullfrogs spawn in small pools near larger bodies of water and are protective of their tadpoles. The male watches over them until he can clear the way for the tadpoles to join a larger pond.
Poison Dart Frogs are known to have different reproductive habits as well. Many Poison Dart Frogs also lay eggs in different puddles to increase chances of survival, and feed their tadpoles during the day remembering exactly where all the eggs were deposited
Female Gastrotheca Ovifera frogs carry their eggs on their backs, while others also carry their tadpoles on their back. Darwin’s Frog eggs are ingested by the male who carries them in his vocal sac until they hop out of his mouth a few weeks later.
Learn more about exceptions to the frog life cycle on our blog
Related Questions About The Frog Life Cycle
What Are The Frog Life Cycle Stages? As a general rule, frogs have 4 main stages within their life cycle, including 1. Egg, 2. Tadpole, 3. Froglet, 4. Adult Frog. The process of evolving through these stages is called metamorphosis and can take up to 28 weeks depending on species and climate.
How Long is Frog Life Cycle? The complete frog life cycle from egg to adult frog can take up to 28 weeks depending on species and climate. It can take 3 to 25 days for an egg to become a tadpole, 14 to 16 weeks for a tadpole to become a froglet, and 6 to 9 weeks to reach adulthood.
What is a Froglet? A froglet is a tadpole that has completed the last stage of metamorphosis and is now a young frog. Froglets have legs, lungs, and a tail that will eventually disappear. A froglet can live above water and eat bugs but is still transforming into an adult frog.
What Is The Difference Between a Frog and a Froglet? A froglet is a small amphibian in the order Anura that completed metamorphosis from a tadpole but is still completing its development to adulthood. A froglet may still have a tail, whereas adult frogs have completed their transformation and no longer have a tail.
Why Are My Tadpoles Not Eating? As a general rule, it is normal that tadpoles do not eat during a certain period of their growth. This is a natural occurrence notably near the end of its transformation to a froglet where it will begin to eat insects.
Why Are My Tadpoles Not Becoming Frogs? Tadpole transformation is initiated by the Thyroid Hormone, and in some rare cases where tadpoles lack the hormone, they will remain at this stage of growth and will not evolve into froglets.
Why Are My Tadpoles Dying? Tadpoles may die if they lack key nutrients and environmental qualities such as unpolluted water, algae and other plant-based foods to feed on, and the presence of few predators.
Chesne, Corinne. La Grenouille. Artémis éd., 2009.
Parsons, Harry. L’univers Des Grenouilles: Amphibiens Poseurs. Éditions Du Trécarré, 2000.
Grenouilles, Crapauds Et Rainettes: Morphologie, Comportement, Alimentation Et Reproduction …, by S. Caratozzolo, De Vecchi, 2008.
Sachs, Laurent M., and Daniel R. Buchholz. “Insufficiency of Thyroid Hormone in Frog Metamorphosis and the Role of Glucocorticoids.” Frontiers, Frontiers, 23 Apr. 2019.