The benevolent toad

July 1, 1993

The benevolent toad

By Robert A. Hedeen, Naturalist

Some years ago a government biologist estimated that each toad in North America was worth at least $35 each year as a destroyer of destructive insects. In view of the continuing upward spiral of inflation, it is probably impossible today to place a precise monetary value on our chubby friend, but one can be sure toads are among the most valuable amphibians as far as man is concerned.

A toad’s appetite is amazing. One researcher found 65 caterpillars of the destructive gypsy moth in a single toad stomach. The same authority estimated that in three months one of these animals would probably devour up to 10,000 insects of various species, some of which, unfortunately, would have been beneficial to man.

The toad’s tongue is attached in the front of the mouth and is elastic and sticky. In a flash, the tongue can be flicked out and back in, ingesting almost anything that looks like it might be edible. A forward lunge of the body by the strong hind legs, coordinated with the 2-inch tongue, can do the job at a surprising distance. I have found many strange, non-food items in toad stomachs: cigarette butts, golf tees, a thumbtack, and a small marble, to name a few. Most toads, however, will, in general, not be interested in an object for food unless there is at least a slight movement involved.

The most common toad in our area is the American toad, but Woodhouse’s toad is known to occur here. These two are closely related, and it takes a toad expert to distinguish between the two. To make identification matters more difficult, sterile hybrids between the two species are sometimes found, but they are rare as the two species have different mating times in the spring, and the distinctive mating call of the males is quite different. These genetic isolating mechanisms are part of nature’s way of preserving the integrity of each species.

Many people lacking an intimate acquaintance with the toad regard it as an ugly, deformed, and even grotesque animal. I am sure, however, that toads appear attractive, if not beautiful, to other toads. Though it is true that in the eyes of man, the toad, with its warty skin, is not as handsome as the sleek-skinned frog, but the beauty of the warty one’s eyes has long been recognized. Even Shakespeare was aware of this when he penned the following:

“Sweet are the uses of adversity,

Which like the toad, ugly and venomous,

Wears yet a precious jewel in its head.”

The pupil of the eye is black, oval in shape, and is surrounded by a broad border of gold. In olden times, this “jewel” was considered to be a good luck charm that protected the wearer from evil spirits.

A species of toad in the tropics secretes a powerful poison that is used by the natives to tip the points of their arrows, but none of the toads found in North America is dangerous in this respect. An oblong gland just behind the eye in our species, however, does manufacture an irritating fluid that serves as a mechanism of defense. Many of us have seen a playful dog take a toad into its mouth and immediately reject it. The pooch is not harmed, but the memory of the burning irritation to its mouth will make it think twice before snapping up another toad in the near future.

Toads and frogs lay their eggs in water. The eggs of toads are embedded in long strings of mucus while the eggs of frogs are enclosed in a ball of the same substance. Both go through the immature tadpole stage.

Most of the many folk stories about toads are without foundation. They do not cause warts if handled, and they don’t squat on mushrooms that are poisonous, so-called toadstools. They do not sometimes excrete a poisonous fluid when handled, unless one considers toad urine to be poisonous.

Toads are long-lived for lower vertebrate animals. One specimen is known to have lived for 36 years, but the idea that they may live for extended periods of time imbedded in the cornerstone of a building is certainly a fable. It never “rains toads,” but when thousands of tadpoles change into baby toads and leave the ponds to find a home on land, especially during a rain storm, they may have appeared to have rained down from above.

In former days, the American toad, Bufo americanus, was the animal most used to introduce freshman students to basic vertebrate anatomy and dissection. Over the years, however, our chunky friend has lost its popularity with biology professors and has been largely replaced by the bullfrog, a decision undoubtedly endorsed and applauded by toads in general.

Dr. Robert Hedeen is a former resident of Maryland’s eastern shore and resided in the Chicago area from 1960-1971. He is a retired professor emeritus of biological sciences in the University of Maryland system. He has published more than 30 scientific papers, has written numerous magazine articles, and is the author of two books on the natural history of the Chesapeake Bay.

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