It can be confusing for people to understand that toads are indeed frogs, but not all frogs are toads. Frogs and toads all belong to the “frog” order, called Anura, which is divided into families. The “true frog” family is called “Ranidae,” and the “true toad” family is called Bufonidae.
Toads are native to areas all over the world except for Australasia, Madagascar, Polynesia and arctic regions. They are nocturnal, shy and prefer to eat insects, grubs, slugs, and worms. They spend most of their time on land, hiding under logs, rocks, porches, or other cool, damp areas.
Toads congregate in creeks or vernal pools in the springtime to mate. People may spot hundreds of toads clustered in a flooded farm field during the day, trilling loudly to call for mates. The vocal sac that expands when the toad trills can be bigger than its head.
Main Differences Between Toads and Frogs
Toads are different from frogs in six main ways:
- Squat bodies with short hind legs — Toads are heavy, clumsy and cannot really jump the way frogs do, so they hop or walk, which can be fatal when they cross roads and highways at night.
- Dry, bumpy skin — Toads do not have warts or cause warts, their skin is only described as “warty.” The skin of the American toad (Bufo americanus) is usually a mixture of brown, gray, olive and red coloring with yellowish bumps and brown or black spots, which provides camouflage from enemies. Some toads have skin that is very leathery and dry. This does not mean they don’t need water. Toads (and frogs) absorb through their skin the water necessary for hydration. They may sit in shallow pools and rub water over their back and head using their legs. During droughts they may retreat underground and lie dormant until it rains.
- Glands that secrete toxins — Toads have large, kidney-shaped parotid glands behind their eyes which secrete a poison that deters enemies, and can harm dogs who go after them. Toxins absorbed into the throat will affect its respiratory system and heart rate. If eaten, toxins entering the bloodstream could be strong enough to cause death. Frogs produce poisons, too, but they are milder. One exception is the dart-poison frog of South America, which can be dangerous simply to hold in one’s hand. The variety of anesthetics, chemicals and hallucinogens found in toad venom have been used for hundreds of years by healers who found value in treating ailments with powdered toad, toad grease or tincture. People have also smoked dried venom or consumed it for hallucinogenic experiences.
- Tiny teeth on the lower jaw — Toads only have teeth on their lower jaw, whereas most frogs have them on the upper and lower jaw, or roof of the mouth. In these amphibians, the teeth help subdue prey that is swallowed live and whole, and are not for chewing.
- Structure of chest cartilage — There are variations in the cartilage found in toad bodies versus frog bodies, which isn’t apparent to casual observers.
- Laying of eggs — Female toads lay eggs in long strings of jelly, which may have four to twelve thousand eggs. These tubes may be up to 70 feet long. Frogs, however, lay eggs in clusters.
The World’s Largest Toad and Other Species
According to David Badger, who wrote the 1995 book entitled Frogs, the ubiquitous cane toad (Bufo marinus) is “presumed to be the world’s largest toad.” He writes that it can get up to 10 inches in length and weigh three pounds, although in the U.S. it averages around seven inches long. The cane toad has become a pest in Hawaii and Australia, where it was introduced.
Fowler’s toad (Bufo woodhousii fowleri), in the southeastern U.S., has an evening cry that sounds like an infant wailing, or baby calf. The Colorado River toad (Bufo alvarius), Badger writes, “is regarded by the western amphibian expert Robert Stebbins as ‘the most spectacular toad of the West.’” This toad rivals the size of the cane toad, and its skin is smooth and leathery like a rhinoceros. Contrary to expectations, the voice of the beefy Colorado River toad is described as a “gentle chirping” or “ferryboat whistle.”
One feature that toads share with frogs (such as bullfrogs and green frogs) is that they have horizontal pupils. A few species of frogs and toads around the world have vertical pupils—or shaped otherwise, like triangular, hourglass, or heart-shaped.
In general terms, anything that looks like a frog is, indeed, a frog by order, but people should refer to the above-mentioned six categories to help make the distinction between true frogs and toads.
Sources:
- Badger, David. Frogs. Stillwater: Voyageur Press, Inc., 1995.
- “Toad.” The New Encyclopedia Britannica, 15th ed., Vol. 11. Chicago: Encyclopedia Britannica, Inc., 2007.
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