Frogs and toads belong to a group of amphibians called Anura, and there are thousands of species of them, living almost everywhere on Earth except Antarctica. They are sorted into families, including Ranidae (true frogs), Hylidae (treefrogs) and Bufonidae (toads). True frogs, such as bullfrogs and pickerel frogs, are the largest of these, and unlike treefrogs, their front toes are not as webbed. Technically, a toad is a kind of frog, and scientists do not draw a firm line between the two: there is no scientific distinction between the names, although most frogs and toads are usually called one or the other.

How fast can a frog catch an insect, and what lets it hold on? In a study of how frogs catch insects, a frog's tongue captured an insect in under 0.07 seconds, five times faster than a human eye blink. A frog cannot see while its tongue is striking, so it can only make a catch by taking careful aim in advance. In a study of frog tongues, low-viscosity (runny) saliva helped the tongue hit and release prey, while high-viscosity (thick) saliva helped it hold on to prey. A frog's eyes also help it swallow: as the frog swallows its prey, the eyes sink through openings in the skull and help force the food down the throat, which is why frogs seem to blink as they eat.

Frogs have more than one way to survive a predator, and several of them are bluffs. Many dull-looking frogs have hidden flash colors, bright patches on the belly, groin or backs of the thighs. A fire-bellied toad's plain brown back matches the ground, but when threatened it shows its red underside, which can startle predators or buy the toad time to escape. The Chilean four-eyed frog has a bright pair of spots on its rump that look like enormous eyes, hidden by its thighs when it sits. When a predator approaches, the frog lowers its head and lifts its rump, creating the illusion of a much larger and more intimidating head. A toad may also puff up its body to look bigger and inedible when a predator is near.

Bright colors on tropical frogs warn predators that they are poisonous, but frogs are not above bluffing: some nonpoisonous species have adopted the colors of poison dart frogs to trick predators into giving them a wide berth they do not deserve. Certain frogs of Central and South America have especially strong poisons in their skin, and there are about 170 kinds of poison dart frogs. In the wild, they are too toxic to touch. Golden poison frogs do not act aggressively toward people; the danger lies in their very toxic skin. Captive ones tend to lose their toxicity without the wild prey that are the source of the toxin, so the poison comes from what the frogs eat in the wild.

A toad's skin has glands that make a poison, which helps protect the toad from predators. A toad's skin is bumpy, a bit like warts, and the large glands behind the eyes are called parotoid glands. The poison is called bufotoxin, and it can kill small animals and cause allergic reactions in people. Because it can irritate people, nobody should lick or eat a toad, and it is best not to handle one. You may have heard that touching a toad gives you warts. In fact, touching a toad does not give you warts.

A tadpole is a young frog that lives in water and breathes with gills. Frog eggs are soft and covered in jelly, and they are usually laid in clusters, while toad eggs are laid in long strings. Tadpoles hatch out of eggs. The change from a tadpole into a frog is called metamorphosis, and during metamorphosis, a tadpole grows legs and its tail is absorbed into its body. Metamorphosis usually takes several weeks. Species that breed in temporary ponds may develop more quickly, because if the pond dries up too soon the underdeveloped tadpoles will perish. By contrast, bullfrog tadpoles may take several years to grow into frogs, and a bullfrog tadpole can take two winters, or almost three years, to turn into a frog.

Explosive breeders gather in large numbers and call for mates for only a few days, using temporary wetlands because there are no fish there to eat their eggs. A male will often stop calling for short periods to pick off a receptive female hopping towards a call. During breeding, female frogs and toads listen carefully and hop closer to males with a deeper or more powerful call, which signals a larger size and a greater ability to survive and reproduce. Larger, more aggressive animals are also better at defending territories where eggs are present. Male frogs and toads call by breathing in air with their lungs and then bouncing the air between their vocal sacs and their lungs.

Not every frog uses a pond. A strawberry poison dart frog lays eggs on land, not in a pond. When the tadpoles are ready to hatch, the mother carries them on her back to water-filled bromeliads in the trees. The tadpoles finish growing in these tiny, predator-free pools, and she feeds them unfertilized eggs. Baby Surinam toads grow up on their mother's back and do not swim around as tadpoles. As of November 2026, the most species-rich genus of frogs is Pristimantis, with more than 500 species, mostly in the Andes of northern South America. Their eggs are laid on land and develop directly into small froglets, bypassing the tadpole stage, and more species are described each year.

Wood frogs spend the winter frozen and thaw out when the weather warms. When blood freezes in most animals, nothing delivers oxygen and nutrients to the organs, so extreme metabolic damage occurs. At the start of a wood frog's winter freeze, its liver makes large amounts of glucose that flush into every cell in its body. A frozen wood frog thaws from the inside outward. Wood frogs and spring peepers can freeze completely in winter, so they can start breeding much earlier than other amphibians. As of November 2026, wood frogs are the only frogs that live north of the Arctic Circle, and scientists do not yet understand what starts a wood frog's heart again after it has been frozen for the winter.

Frogs and toads eat so many insects that they help keep a large part of the world's insect numbers down. People brought cane toads to Australia in 1935 to kill sugarcane beetles. Several attempts to control insect pests failed when Bufo marinus, the cane toad, was introduced into regions where toads are not native, including Australia and Papua New Guinea. Cane toads have voracious appetites and do not restrict themselves to eating unwanted insects. As of November 2026, cane toads are the largest toads and grow up to 9 inches (23 centimeters) long, and bullfrogs that people have introduced may be driving native frogs to extinction in some areas.

As of November 2026, the record includes a 2004 global assessment that found that nearly one-third of the world's amphibians are threatened, representing 1,856 species. AmphibiaWeb adds that, in the last three decades before its 2021 update, nearly 168 species are believed to have gone extinct and over 43% more have declining populations. As of November 2026, most scientists agree that there is a worldwide decline in frog numbers, and habitat loss and invasive species are among the biggest threats to frogs and toads. As of November 2026, a fungus disease called chytrid is causing severe declines in many frog populations. Amphibians react strongly to changes in their surroundings, so scientists use them as signs of how healthy a place is.

Words to know

• metamorphosis: tadpole becoming frog
• bluffing: faking strength
• voracious: extremely hungry