Ranidae

True frogs live in many places.

They live on almost every land. They live on every continent but Antarctica.

These frogs have smooth and wet skin. They have big, strong legs. They also have webbed feet.

This helps them move.

Some frogs are very small. Other frogs are very large. Most like to live near water. They lay eggs in the water. The eggs turn into tadpoles.

Some frogs even live in trees. A few can live in salty water. It is fun to see them!

Can you find a frog? Do you like to jump too?

True frogs are a big family of frogs.

They live in many parts of the world. You can find them on every continent except Antarctica. They live in North America and South America. They also live in Europe, Africa, and Asia. One kind lives in northern Australia.

Most true frogs have smooth and wet skin. They have large, strong legs for jumping. They also have webbed feet to help them swim.

These frogs come in many sizes. Some are very small. Others are very large.

Many true frogs live near water. Most lay their eggs in the water. These eggs grow into tadpoles. Some frogs live in trees. A few can even live in brackish water. This is water that is a mix of fresh and salt water.

Scientists study how these frogs are related. They use genes to learn about their history. New studies help us learn more about them every day. There are many different groups of true frogs. Some groups have many species. Other groups have only one species.

True frogs belong to a family called Ranidae. These frogs are very special because they live almost everywhere. You can find them on every continent except Antarctica. They live in North America and northern South America. They are also found in Europe and Africa. Many live in Asia, from the East Indies to New Guinea. One single species, the Australian wood frog, lives in northern Australia.

Most true frogs have a certain way they look and move. Their skin is usually smooth and moist. They have large and powerful legs for jumping. They also have feet with webbing between the toes. This webbing helps them swim through the water. These frogs come in many different sizes. The wood frog is quite small. Other species in the family can be very large.

Many of these frogs live close to water. Most species lay their eggs in the water. These eggs hatch into tadpoles. Some true frogs live in trees instead. A very small number can even live in brackish water. This is water that is a mix of fresh and salt water. This shows how much they can live in different places. They can live in many different kinds of homes.

Scientists study the history of these frogs. They want to know how they changed over time. Some think they started in a place called India. Long ago, India moved and hit Asia. This might have helped the frogs move to new lands. Other studies say they actually started in Eurasia. These frogs began to spread out of Asia at the end of the Eocene. By the time the Miocene began, they were on almost every continent.

There are many different groups of true frogs. Scientists use names like genera to group them. The genus Rana is a well-known group. The genus Amolops is a large group with 80 species. Another group is Odorrana, which has 64 species. The genus Lithobates has 55 species. Some groups are very small. For example, the genus Huia has only one species. Scientists are still studying these groups today.

Ranidae is a large family of amphibians commonly known as "true frogs." These animals are highly successful because they have a massive global presence. They are considered cosmopolitan, meaning they are found across the world. In fact, true frogs live on every continent except for Antarctica. Their range includes North America and northern South America. They are also found throughout Europe and Africa, including the island of Madagascar. In Asia, their territory stretches from the East Indies all the way to New Guinea. One specific species, the Australian wood frog, has even spread into the far north of Australia.

Most members of this family share specific physical traits that help them survive. They typically possess smooth and moist skin. To move through their environments, they use large and powerful legs. Their feet are often extensively webbed, which aids in swimming. The size of true frogs varies significantly between different species. For instance, the wood frog is quite small. Other species within the Ranidae family can grow to be very large. While many are aquatic or live very close to water, they occupy many different habitats. Some are arboreal, meaning they live in trees. A few rare species can even survive in brackish water, which is a mix of fresh and salt water.

The life cycle of most true frogs involves a distinct transition. Most species lay their eggs directly in the water. Once the eggs hatch, the young undergo a tadpole stage. This process allows them to live in aquatic environments before reaching adulthood. This developmental path is common to most frog families. However, the family Ranidae shows incredible variation in where these life stages take place. This flexibility allows them to inhabit many different ecological niches around the globe.

Scientists are still researching the evolutionary history of the Ranidae. There are different theories about where they first began. One theory suggests they had Gondwanan origins. This idea proposes they evolved on Insular India during the Cretaceous period. Under this theory, they stayed in the Indian subcontinent until the late Eocene. When India collided with Asia, the frogs could colonize Eurasia and the rest of the world. However, more recent studies suggest a different path. These studies propose that the Ranidae actually originated in Eurasia. They suggest that related lineages colonized India from Eurasia during the Paleogene period.

Understanding the exact relationship between these frogs and others is complex. The Ranidae are related to several other families, such as Rhacophoridae and Dicroglossidae. Some researchers believe they are most closely related to Nyctibatrachidae, a group found only in India. These two groups may have diverged during the early Eocene. Other studies, however, suggest a closer link to the Dicroglossidae family. The Ranidae began to spread out of Asia at the end of the Eocene. By the beginning of the Miocene, they had successfully colonized almost every continent.

Modern science is still working to organize the many groups within Ranidae. This process is called systematics, and it involves classifying organisms into groups. The subdivisions of Ranidae are currently a matter of scientific dispute. Many former subfamilies have been moved into their own separate families. These include Petropedetidae, Cacosterninae, Mantellidae, and Dicroglossidae. The genus Rana, which was once very large, has been split into much smaller groups. Today, scientists recognize many different genera. For example, the genus Amolops contains 80 different species. The genus Odorrana is also large, with 64 species. Other groups are much smaller, like the genus Huia, which contains only one species.

Because there is so much diversity, some classifications remain uncertain. In 2023, one group of experts tentatively moved several genera into the genus Hylarana. These included Amnirana, Chalcorana, Humerana, Hydrophylax, Indosylvirana, Papurana, Pulchrana, and Sylvirana. They did this to clear up taxonomic confusion. However, other organizations like AmphibiaWeb do not recognize these changes. Some species are even placed in a category called incertae sedis. This term is used when a species' taxonomic status is too uncertain for specific placement. This constant movement in scientific naming shows how much we are still learning about these animals.