Frogs are amphibians, which means they live part of their lives in water and part on land. They have adaptations that enable them to thrive in both environments.
Frogs have webbed feet for swimming and propelling themselves through the water. When swimming, a frog will kick its hind legs in unison, generating a forward thrust and propelling itself through the water. The webbed feet act as the main propulsive unit, pushing large volumes of water behind.
Apart from webbed feet, most frogs have streamlined bodies, which enable them to move efficiently through the water.
That said, it is important to note that not all frogs have webbed feet.
There are over 7,000 frog species around the world – found in a wide variety of habitats, from rainforests to mountainous areas, to dry regions.
Different frog species have adapted to their environments and developed physical adaptions that are practical for the areas they live in.
Some frogs only have a small amount of webbing, and some do not have any webbing on their feet at all (more information on that is below).
Frogs Have Webbed Feet for Swimming
Most frogs spend a significant amount of their time in the water and are well-adapted for swimming.
They have extensive webbing between their toes, streamlined bodies, and powerful hind legs to propel themselves through the water.
When a frog kicks its legs in unison, it generates a forward thrust that propels it through the water.
Although most frogs have some webbing on their feet, highly aquatic species like the African clawed frog tend to have extensive webbing that goes all the way to the end of their toes.
The webbed feet act as the main propulsive unit, pushing the frog’s streamlined body through the water.
Tree Frogs Have Toe Pads, in Addition to Webbed Feet
Tree frogs are arboreal in their adult stage, and spend most of their time in or around trees. They live a highly terrestrial life and often only go the water during the breeding season, to mate and lay their eggs.
Tree frogs generally have small light bodies that allow them to sit on leaves and cling to weak branches without falling. They also have long toes that allow them to wrap around small branches.
Their toes have large, round toe pads that help them cling to branches. These toe pads work like suction cups to help the frog cling to wet leaves and other smooth surfaces. These “sticky toes” mean tree frogs can even cling to glass!
Toads Have Hardened Knobs, in Addition to Webbed Feet
Toads generally live a more terrestrial life than true frogs. For this reason, their feet are more adapted for terrestrial movement rather than swimming.
They typically have short hind legs for hopping short distances, and and little webbing on their feet.
This is in contrast to most true frogs which have long powerful hind legs and fully webbed feet.
Since toads spend the majority of their time on dry land, their hind feet are more adapted for digging burrows in soft soil or mulch where the toad can hide and protect itself from the elements.
Many toads have special, hardened knobs on the toes of their hind legs, that help them dig into the soil.
They use their back legs to ‘knead’ their bodies into the soil, submerging themselves completely.
Toads can burrow anywhere from 6 inches to over 3 feet deep!
Some Frogs Have Webbed Feet for ‘Flying’
Some frogs, such as those of the genus Rhacophorus, are known as ‘flying frogs’ or ‘gliding frogs’. These frogs can go long distances at a fast pace, by ‘flying’,
These frogs don’t truly fly, as birds or bats do. What they do is glide—somewhat like humans piloting a hang glider.
When threatened or in search of prey, flying frogs launch their lightweight bodies from a high branch into the air. They spread out their large webbed feet and hands, as well as special flaps of skin on their legs and arms.
These membranes of skin act like miniature parachutes to slow the frog’s descent.
Some flying frogs glide as far as 40 or 50 feet to a neighboring tree branch or even all the way to the ground. They also have oversized toe pads to help them land softly and stick to tree trunks.
Gliding is an energy-efficient way to quickly move from one place to another.
Not All Frogs Have Webbed Feet
Although most frogs have webbed feet, some frogs do not have any webbing on their feet.
Frogs such as the Common Rain Frogs (Breviceps adspersus) found in southern Africa are entirely terrestrial and do not have any webbing between their toes. These frogs are not able to swim, or even jump.
They have a round body, and short arms and move by either walking or running.
Common rain frogs are excellent burrowers, and spend most of their time underground, using only emerging during the wet season.
Common Questions
What are the functions of frogs’ webbed feet? The main function of frogs’ webbed feet is to help them swim through the water. When a frog swims, it will kick its legs back, and the webbed feet act as propellers, pushing the frog forward. Some frogs (known as flying frogs), also use their webbed feet as mini parachutes to glide through the air.
Do all frogs have webbed feet? Although most frogs have webbed feet, not all species do. Some frogs such as the the Common Rain Frogs (Breviceps adspersus) of Southern Africa are fully terrestrial and do not have any webbing between their toes.
Conclusion
There are over 7,000 frog species in the world. Most of these species reproduce or spend some time in the water, and have webbed feet to help them move in this aquatic environment.
However, not all have equal webbing. Highly aquatic frogs such as the African clawed frog, tend to have more extensive webbing that goes all the way to the end of their toes.
This is in contrast to more terrestrial species, like tree frogs, that usually have smaller pads of webbing on their feet.
Some frog species, such as the African rain frogs do not have webbed feet, as they live entirely on land. These frogs reproduce on land and do not spend any part of their life in the water.
Sources:
Cynthia Bix and Diana Landa (1996). Flying Frog: Glider in the Treetops. Animal Athletes: Olympians of the Wild World (PDF).
Fan Jizhuang, Zhang Wei, Yuan Bowen, Liu Gangfeng; Propulsive efficiency of frog swimming with different feet and swimming patterns. Biol Open 15 April 2017; 6 (4): 503–510. doi: https://doi.org/10.1242/bio.022913