Genera: there are at least 303 known frog and toad genera
Species: there are about 4,000 known frog and toad species
Length: largest—Goliath frog Conraua goliath is 13.5 inches (30 centimeters); smallest—gold frog Psllophryne didactyla is 0.39 inches (1 centimeter)
Weight: up to 6.6 pounds (3 kilograms) for Goliath frog
Life span: 1 to 30 years
Number of eggs laid: from 2 to more than 50,000, depending on the species
Incubation: 14 to 23 days
Age of maturity: 2 months to 1 year
Conservation status: many species are at critical risk, including the golden toad Bufo periglenes, the Mallorcan midwife toad Alytes muletensis, and the spotted frog Litoria spenceri
The Panamanian golden frog Atelopus zeteki may only measure 1 to 2 inches (2 to 5 centimeters) in length, but it's a huge star in its native Panama, where it appears on everything from tourist guides to lottery tickets.
African frogs Rana fascinata are the best jumpers of the frogs and toads. They can hop 14 feet (4.2 meters) in a single bound!
Spadefoot toads (family Pelobatidae) can act as amphibian weather forecasters. Before a rainstorm they come out by the hundreds to croak something that sounds like, "Rain-today, rain-today." Then people who live nearby know to expect a storm.
The poison frogs (family Dendrobatidae) get their name from a tribe of people in the Colombian rain forest. They catch the frogs with leaves and then dip their blow darts into the frog's poisonous skin secretions to use for hunting.
Horny toads are not really toads, they're lizards. So you won't be learning about them here!
Listen to tree frogs!
Amphibians: Frog & Toad
almost everywhere on Earth except Antarctica, the Arctic,
Frog or toad?
Frogs have long legs that are good for hopping, skin that is smooth and moist, and special pads on their toes that help them climb. Toads, on the other hand, are more heavyset with shorter legs, and usually have drier skin, often with warty-looking bumps. Frogs are more likely to live in or near water than toads. The word "frogs" can include both frogs and toads, as some frogs may not live near water and some toads have smooth skin. Can you get warts from holding a toad? No! But you can die from holding a frog—if it's a poison dart frog! Some of these bright little South American frogs are so toxic that one drop of their skin secretions can kill an adult human.
When you look at a frog or a toad, you'll notice that it doesn't seem to have a neck. Practically speaking, this is true. Most frog and toad species have large, protruding eyes so they can see in most directions. They can also hop around to look in another direction. But they can't turn their heads like we can, since their necks are almost non-existent.
When is a fish not a fish?
When it's a tadpole! Most frogs and toads start life out in the water. The mother lays her eggs in water, or at least in a moist place like a dew-collecting leaf or plant. The eggs hatch into tadpoles (also known as pollywogs or froglets) that look like funny, big-headed fish. Then they gradually grow legs, absorb their tails, lose their gills, and eventually turn into frogs and toads that start breathing air and hopping.
It's all a matter of survival
Adult frogs and toads have two main color schemes. Each one signals a different survival technique. Those with bright colors (like poison dart frogs) are easy to see and warn potential predators that the frog is toxic. The hoppers with mottled green or brown colors are camouflaged so predators have a hard time finding them. Toads have additional survival techniques as well. If a predator is after them, they puff themselves up so they look too big to swallow. Most toads can also secrete a burning milky toxin from a gland behind their eyes!
What's for dinner?
Most frogs and toads eat insects, spiders, worms, and slugs. Some of the larger species will go for mice and other small rodents, and even other small reptiles and amphibians. At the San Diego Zoo they are fed crickets, worms, fruit flies, or mice.
Hoppers are responsible for keeping a large part of the world's insect population under control. In some cases, however, their appetites can be a problem. Latin American cane toads Bufo marinus were introduced to Australia in 1935 to kill sugarcane beetles. But instead of beetles, the toads preferred to eat native frogs, small marsupials, and snakes. Not only that, but they poisoned everything that tried to eat them, including rare animals like Tasmanian devils and pet dogs! Since they lay more than 50,000 eggs at a time, they turned into bigger pests than the beetles they were supposed to get rid of.
A ribbeting chorus
Have you ever walked past a pond or creek at night and heard lots of frogs croaking and ribbeting like a giant froggy chorus? It's likely you're hearing a bunch of male frogs making calls to attract females. Each frog species has a different call that is used to attract mates and warn off rivals. When a female picks a male whose call she likes, the male grabs her and she lets out all her eggs. Then he fertilizes the eggs and in some species also guards them.
Dad takes the lead
In many species of hoppers it is the dad that cares for the eggs. He may transport the eggs to a safe, wet place by putting them on his back, in a pouch on his belly, or even in his mouth. Or he may wait until the eggs hatch into tadpoles before he transports them from a wet place on land to actual water. Although the dad is more likely to perform these tasks, the moms often do too. Sometimes both parents do the babysitting—it depends on the species. The highly endangered Australian gastric-brooding frog Rheobatrachus silus has one of the weirdest ways to care for eggs. The female eats as many as 20 eggs after the male fertilizes them. Then she stops eating regular food, because the eggs are developing in her stomach! When they've begun to turn into tadpoles, she vomits them up and starts eating again!
What does the future hold?
It's hard to get a handle on the world's frog and toad populations, because there are so many of them in so many hard-to-find places. But there is enough information to suggest that we should be worried. In the 1980s, scientists began getting reports from all over the world about disappearing amphibian populations, even in protected areas! The loss of wetlands and other frog habitat because of industry and human population growth is one of the biggest causes. Also the increase of roads has been hard on migrating frogs. When hoppers try to cross a highway to get to their breeding pools, they get squashed by cars. Then there are non-native species like trout and even other frogs that humans introduce. The non-natives often eat all the local native frogs. There are also pollutants that get into the rivers and ponds and kill the frogs and tadpoles.