One of the most amazing things about frogs is that there are over 7,500 different kinds and more being discovered every month by scientists around the world. Since there are so many frogs species, their size and weight can greatly vary from one frog to another.
As a general rule, the average weight of frogs is around 22.7 g (0.80 oz), but some frogs can reach 3 kg (7.2 lb) while other frogs are as light as 0.01 g (0.0003 oz). A frog’s weight mostly depends on the species, but can also be influenced by availability of food, predation, and environment.
This table includes a variety of frog species and their average weight:
|Frog Species||Average Length (cm)||Average Weight (g)|
|Mimic Poison Frog||1-2||1-2|
|Blue Poison Dart Frog||2-4||8-10|
|Golden Poison Frog||2-5||8-10|
|Northern Leopard Frog||5-12||22-25|
|Red-eyed Tree Frog||5-6.5||5-15|
|African Dwarf Frog||5-6.5||2-5|
|Amazon Milk Frog||6-10||4-5|
|Australian Green Tree Frog||10-11.5||175-250|
|Argentine Horned Frog (Pacman Frog)||10-17||225-500|
When it comes to frog size and weight, frogs vary profoundly depending notably on the species. Frogs also have to adapt to certain environmental conditions, forcing them to evolve to reach certain sizes. This is why some frogs tend to be gigantic in frog standards while other frogs are no bigger than a penny.
What Influences Frog Weight?
With over 7,500 known frogs, the species is the main factor that influence the weight a frog may attain. However, age, food availability, predation, temperature, humidity, time of year, and overall environment also influence how much a frog may weigh.
Here is an explanation as to what factors influence frog weight:
- Species: This is the main factor that influences frog weight since genetics often dictate how heavy or light a frog will be depending on the species. Tree frogs are often much lighter than aquatic or terrestrial frogs because they climb trees and live on leaves and branches.
- Age: Age is also an important factor since frogs undergo profound metamorphic changes through their life cycle. Eggs, tadpoles, and froglets are generally lighter than adult frogs.
- Food: Frogs that have abundant access to food will generally weigh more than frogs that have scarce access to food.
- Temperature: Temperature and humidity may play a role in a frogs weight as a study found that “the rate of weight loss was significantly higher at high temperatures than at low temperatures and increased logarithmically with temperature” (Jameson, 1966).
- Predation: If there are many predators around, it may be harder for frogs to survive and access food. Needing to escape predators takes up energy which can prevent a frog from gaining weight. Some frogs also need to grow large enough to survive among larger predators within their environment.
- Environment: A frog in a predator-free, food-abundant environment will tend to be larger than a frog that is constantly under pressure or stress within their environment.
- Time of year: Frogs are generally lighter after hibernation or estivation, and generally larger or heavier before hibernation or estivation as part of their preparation for this process.
There were a few toads that roamed my yard when I was a kid and one of them was very skinny at the beginning of Summer, but had a very large stomach by the end of the Summer thanks to the abundant presence of bugs and the absence of predators.
Some frogs are so light that you can’t even feel a thing when you try to carry them. Meanwhile, other frogs species are so large they can eat mice, bats, and small mammals.
Which Species Of Frogs Is The Heaviest?
Goliath Frogs are the heaviest known and alive frog species at 32 cm or 12.5 inches and weighing 3.3 kg or nearly 7.3 pounds. However, the extinct Beelzebufo is said to have reached 42.5 cm or nearly 17 inches long which would have made it much heavier than Goliath Frogs.
The heaviest frog species is also the world’s largest frog. Goliath Frogs can be found in the equator area of West Africa and are the largest and heaviest frogs we have in the world today.
However, there was a time when the Goliath Frog was not the biggest frog on the planet. Beelzebufo ampinga, or simply Beelzebufo, is a prehistoric species of frog that is said to have lived in Madagascar 70 million years ago.
In a way, this is the dinosaur ancestor of the frogs we have today as they could reach lengths of 42.5 cm or nearly 17 inches long. There is no clear indication of how heavy Beelzebufo was, but it would have been much heavier than the Goliath Frog since it is larger.
Which Species Of Frogs Is The Lightest?
The world’s smallest known frog species is Paedophryne amanuensis with an average length of 0.77 cm and weight of 0.01 grams. This frog is so tiny that it is much smaller than a human fingernail.
The size difference between the world’s biggest frog and the world’s smallest frog is so huge that the Goliath Frog is about 3,300 times heavier than the Paedophryne amanuensis.
Paedophryne amanuensis were recently discovered (Rittmeyer et al, 2012) in Papua New Guinea. A group of scientists was able to discover the frog species by tracing loud frog calls at night. This brought them to some leaf litter, which they carefully looked through until they saw plenty of tiny frogs hopping around.
The reason why these frogs are so small can be tied to the fact that they like living in leaf litter while eating very small insects that also live in such places. Frogs that also live in leaf litter tend to be small, like the Spring Peeper which can be very difficult to spot in the wild as I demonstrate below:
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More About Frog Sizes
Learn more about different frogs species, their weight and size on our blog:
- How Big Can Frogs Get?
- Frog Profiles: More About The Size, Weight, And Features of Different Frog Species
- Frog Anatomy: Everything You Need To Know
Jameson, David L. “Rate of Weight Loss of Tree Frogs at Various Temperatures and Humidities.” Ecology, vol. 47, no. 4, Ecological Society of America, 1966, pp. 605–13, https://doi.org/10.2307/1933938.
Eric N. Rittmeyer, Allen Allison, Michael C. Gründler, Derrick K. Thompson, Christopher C. Austin, Ecological Guild Evolution and the Discovery of the World’s Smallest Vertebrate, January 11, 2012 https://doi.org/10.1371/journal.pone.0029797