What are frogs and toads?

Frogs and toads are tailless amphibians belonging to the order Anura. While the term "frog" can refer specifically to the family Ranidae, it's often used to differentiate smooth-skinned, leaping anurans from squat, warty, hopping ones, known as toads. However, the distinction isn't strict, as all toads are technically frogs, with differences being mostly superficial. Adult frogs and toads are recognized by their short bodies, elongated hind limbs, and lack of a visible neck or tail. They inhabit diverse environments worldwide, except for extremely cold regions and some oceanic islands. While frogs are diverse in the tropics, habitat destruction and diseases like the amphibian chytrid fungus have severely impacted many frog populations.

What are the main differences between frogs and toads?

Though differentiating between frogs and toads can be difficult, there are a few features that may help with amphibian identification. If the amphibian has smooth and moist skin, it is likely a frog, while dry, rough, and bumpy skin suggests it is a toad. Frogs are often found near water because they need to keep their skin moist, whereas toads' skin retains moisture better, so they don't need to be near water. Also, the hind legs of frogs are generally longer than their head and body, which gives them the ability to leap far. Toads' hind legs are shorter, so they transport themselves with small hops. Both frogs and toads are tailless amphibians belonging to the order Anura . All toads fit into the category of frogs, and the differences are mostly superficial.

What is an amphibian?

An amphibian is a vertebrate known for thriving in both water and on land, a trait reflected in their name, which means "living a double life". They first appeared roughly 340 million years ago. The three orders of amphibians that exist today are frogs and toads (order Anura), newts and salamanders (order Caudata), and caecilians (order Gymnophiona). Frogs and toads are tailless amphibians with strong hind legs for leaping. While the terms "frog" and "toad" are often used to describe different types of anurans, they aren't formal taxonomic categories. All toads are frogs, but the terms typically distinguish between smooth-skinned, leaping anurans (frogs) and squat, warty, hopping ones (toads).

How do frogs and toads grow and change during their life cycles?

During their life cycles, frogs and toads undergo metamorphosis , a transformation from a larval stage to an adult form. Many frogs have a free-swimming larval stage called a tadpole . Tadpoles have short oval bodies, broad tails, and internal gills concealed by a covering. As tadpoles grow, they develop hind limb buds, which differentiate into hind limbs with toes, webbing, and tubercles. Later, forelimbs emerge, and the tail shrinks as it is absorbed by the body. The mouth changes, with jaws and teeth developing as horny denticles disappear. Eyelids develop, mucous glands form in the skin, and the skeleton ossifies. The long, coiled intestine of the tadpole shrinks to the shorter intestine of the adult. Most tadpoles complete their development in two or three months, though some take only two weeks, and bullfrogs can take three years.

What roles do frogs and toads play in the environment?

Frogs and toads, members of the amphibian order Anura, play several important roles in the environment. As tadpoles, many species feed on algae and vegetation, while stream tadpoles graze on bacteria, helping to maintain the balance of their aquatic ecosystems. Adult frogs and toads are carnivores, consuming insects and other invertebrates, thus controlling populations of potential pests. Some larger species may also eat small rodents or other frogs. In turn, frogs and toads serve as a food source for various predators like snakes, birds, and mammals. Additionally, they are economically useful in reducing the number of insects that destroy crops or transmit diseases.

frog and toad

Images & Videos

Three painted reed frogs with yellow and brown markings sit on green fern leaves.

Witness the bullfrog's powerful action, generated by its hind legs, as it jumps through a field

A bright yellow-green polka-dot treefrog (Hypsiboas punctatus) with large eyes sits on a broad leaf, facing the camera against a dark background.

How hibernating frogs survive in freezing temperatures

Illustration showing different breeding specializations in anurans, including Hemiphractus with eggs on its back, Phyllomedusa eggs on a leaf, Colostethus male carrying tadpoles, aquatic eggs free-floating or attached to vegetation, Physalaemus pair with foam nest, and Gastrotheca with eggs in a pouch.

See toads engage in amphibious amplexus and witness metamorphosis of tadpoles into toads

frog and toad

amphibian order

Also known as: Anura, anuran, salientian

Written by

William E. DuellmanAll

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Britannica Editors

History

Top Questions

What are frogs and toads?
Frogs and toads are tailless amphibians belonging to the order Anura. While the term "frog" can refer specifically to the family Ranidae, it's often used to differentiate smooth-skinned, leaping anurans from squat, warty, hopping ones, known as toads. However, the distinction isn't strict, as all toads are technically frogs, with differences being mostly superficial.

Adult frogs and toads are recognized by their short bodies, elongated hind limbs, and lack of a visible neck or tail. They inhabit diverse environments worldwide, except for extremely cold regions and some oceanic islands. While frogs are diverse in the tropics, habitat destruction and diseases like the amphibian chytrid fungus have severely impacted many frog populations.
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How are frogs and toads similar?
Frogs and toads, belonging to the amphibian order Anura, share several key characteristics. As amphibians, both can exploit aquatic and terrestrial habitats. Adult frogs and toads are recognized by their short bodies, elongated hind limbs, absence of a visible neck, and lack of a tail. The name frog is commonly applied to those forms with long legs and smooth mucus-covered skins, while toad is used for a variety of robust short-legged forms, especially those with rough skins.

Both frogs and toads undergo a larval stage as tadpoles, which then metamorphose into adults, developing limbs and losing their tails. They are found worldwide except in extremely cold regions and some oceanic islands. Their diet primarily consists of insects and other small invertebrates.
3 Britannica Sources
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What are the main differences between frogs and toads?
Though differentiating between frogs and toads can be difficult, there are a few features that may help with amphibian identification. If the amphibian has smooth and moist skin, it is likely a frog, while dry, rough, and bumpy skin suggests it is a toad. Frogs are often found near water because they need to keep their skin moist, whereas toads' skin retains moisture better, so they don't need to be near water. Also, the hind legs of frogs are generally longer than their head and body, which gives them the ability to leap far. Toads' hind legs are shorter, so they transport themselves with small hops.

Both frogs and toads are tailless amphibians belonging to the order Anura. All toads fit into the category of frogs, and the differences are mostly superficial.
3 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What is an amphibian?
An amphibian is a vertebrate known for thriving in both water and on land, a trait reflected in their name, which means "living a double life". They first appeared roughly 340 million years ago. The three orders of amphibians that exist today are frogs and toads (order Anura), newts and salamanders (order Caudata), and caecilians (order Gymnophiona).

Frogs and toads are tailless amphibians with strong hind legs for leaping. While the terms "frog" and "toad" are often used to describe different types of anurans, they aren't formal taxonomic categories. All toads are frogs, but the terms typically distinguish between smooth-skinned, leaping anurans (frogs) and squat, warty, hopping ones (toads).
5 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
How do frogs and toads grow and change during their life cycles?
During their life cycles, frogs and toads undergo metamorphosis, a transformation from a larval stage to an adult form. Many frogs have a free-swimming larval stage called a tadpole. Tadpoles have short oval bodies, broad tails, and internal gills concealed by a covering.

As tadpoles grow, they develop hind limb buds, which differentiate into hind limbs with toes, webbing, and tubercles. Later, forelimbs emerge, and the tail shrinks as it is absorbed by the body. The mouth changes, with jaws and teeth developing as horny denticles disappear. Eyelids develop, mucous glands form in the skin, and the skeleton ossifies. The long, coiled intestine of the tadpole shrinks to the shorter intestine of the adult. Most tadpoles complete their development in two or three months, though some take only two weeks, and bullfrogs can take three years.
4 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What roles do frogs and toads play in the environment?
Frogs and toads, members of the amphibian order Anura, play several important roles in the environment. As tadpoles, many species feed on algae and vegetation, while stream tadpoles graze on bacteria, helping to maintain the balance of their aquatic ecosystems.

Adult frogs and toads are carnivores, consuming insects and other invertebrates, thus controlling populations of potential pests. Some larger species may also eat small rodents or other frogs. In turn, frogs and toads serve as a food source for various predators like snakes, birds, and mammals. Additionally, they are economically useful in reducing the number of insects that destroy crops or transmit diseases.
4 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

painted reed frogPainted reed frogs (*Hyperolius viridiflavus*).

frog and toad, (order Anura), amphibians belonging to the order Anura, which, because of their wide distribution, are known by most people around the world. The name frog is commonly applied to those forms with long legs and smooth mucus-covered skins, while toad is used for a variety of robust short-legged forms, especially those with rough skins. The name toad is applied so unevenly that one member of a family may be called a toad and a closely related member a frog. The familiar members of the family Bufonidae may be distinguished as “true toads.” In this article, frog is applied generally to all members of order Anura and toad to those for which it has traditionally been used. There are roughly 7,300 species of living frogs and toads.

Frogs are used as teaching tools from grade school through college. One of the first biology lessons many children receive is through the rearing of the larvae, known as tadpoles or pollywogs, in science classes. Students become familiar with frog anatomy and embryology in biology courses.

People in various parts of the world eat frog legs, and some kinds of toads are used in insect control. Certain South American Indians use the poisonous secretions of some kinds of frogs for poison arrows and darts (see poison frog), and now biochemists are studying the possible medical uses of the constituents of the poison. The biologist interested in evolution finds a vast array of interesting and often perplexing problems in the study of frogs, such as the relatively sudden decline of many frog species since the late 20th century.

General features

Size range and diversity of structure

Although all frogs are readily recognizable, there are great varieties of sizes and of structural modifications. Many frogs are tiny animals; perhaps the smallest is the Brazilian Psyllophryne didactyla, adults of which measure 9.8 mm (0.4 inch) or less in body length (with legs drawn in). However, the West African goliath frog, Conraua goliath, has a body length of nearly 300 mm (12 inches). Many frogs and toads have smooth moist skins. Toads of the genus Bufo are familiar as “warty” amphibians, the skin being highly glandular and covered with tubercles (small, round nodules). Frogs of many other families have rough tubercular skins, usually an adaptation for life in the less humid environments. The opposite extreme is found in the small arboreal (tree-dwelling) frogs of the tropical American family Centrolenidae, in which the skin on the underside is so thin and transparent that the heart and viscera can be seen through the skin. In most species, cutaneous gas exchange (that is, breathing through the skin) supplements the oxygen taken in by the lungs; however, the lungless Barbourula kalimantanensis of Borneo obtains all its oxygen through its skin.

Pronounced structural differences between species can also appear in the head. Whereas the head in many species is smooth and rounded, some species diverge from this pattern. The skull of the Malayan leaf frog (Megophrys nasuta) has evolved to mimic the shape and texture of leaf litter on the forest floor. The head of the banded horned tree frog (Hemiphractus fasciatus) is triangular with hard bony hornlike processes above its eyes and near the rear of its skull. Likewise, the shovel-headed tree frog (Triprion spatulatus) has a wide skull that shields the rest of its body from attack, whereas disc frogs (Synapturanus) have developed pointed snouts that aid in burrowing.

Sea otter (Enhydra lutris), also called great sea otter, rare, completely marine otter of the northern Pacific, usually found in kelp beds. Floats on back. Looks like sea otter laughing. saltwater otters

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Animal Group Names

polka-dot tree frogPolka-dot tree frog (*Hypsiboas punctatus*).

Most frogs move by leaping. The long and powerful hind limbs are straightened rapidly from the crouching position, propelling the frog through the air. Many arboreal frogs—especially members of the families Hylidae, Rhacophoridae, Centrolenidae, and others—have adhesive disks on the ends of the fingers and toes and leap from branch to branch or from leaf to leaf (see tree frog). The families Bufonidae, Rhinophrynidae, and Microhylidae and certain burrowing species in other families have relatively short hind limbs and move forward by series of short hops. Some bufonids actually walk instead of hop. Highly modified members of the hylid subfamily Phyllomedusinae have opposable digits on the hands and feet and walk slowly along branches, deliberately grasping the branch in the manner of tiny lemurs. Many kinds of frogs have membranous webbing between the fingers and toes; in the aquatic species, the webbing on the feet aids in swimming. The extreme in this specialization is seen in the aquatic family Pipidae. Members of that family normally never leave the water. In regions of the Earth subjected to long dry periods, frogs must seek cover to avoid desiccation; they have behavioral and structural adaptations to conserve water.

leopard frogLeopard frog (*Lithobates pipiens*).

Although many frogs are unimpressively coloured, some species are brilliantly marked. The most common colours are brown, gray, green, and yellow. Uniformly coloured frogs are the exception rather than the rule. The markings of a frog may seem bold when observed out of the natural habitat, but they usually are concealing or visually disruptive when the frog is in its environment (see below coloration).

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Distribution and abundance

Because of their morphological and physiological adaptations, frogs are able to inhabit most regions of the world except the extremely cold landmasses at high latitudes and some oceanic islands that they have been unable to colonize because of the barriers provided by salt water. Frogs live in desert regions below sea level and in montane areas up to elevations above 4,560 metres (15,000 feet). Some members of the genus Rana live north of the Arctic Circle. Although widely distributed on Earth, frogs are most diverse and abundant in the tropics, and five or six of the 28 families are restricted to the tropics. In most temperate areas of the world, the number of species of frogs at any one locality is usually fewer than 10, but in the tropics, especially in rainforests, the number of species is much greater. At one locality in the upper Amazon basin in eastern Ecuador, 83 species are known to occur, about the same number as is known for all of the United States.

In a complex environment such as a tropical rainforest, the large number of species of frogs partition the environmental resources in a variety of ways. In the humid tropics, frogs can be active throughout the year, but many species are seasonal in their breeding activity. Various kinds of sites and different seasons are used for calling and egg laying; such temporal and spatial separation avoids interspecific competition. Frogs feed mostly on insects and other invertebrates, and the abundance of food in tropical rainforests probably places no competitive restrictions on this aspect of environmental resources. Some large species eat vertebrates, including small rodents and other frogs.

frog and toad

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General features

Size range and diversity of structure

Distribution and abundance