Many readers have probably seen their dogs catch toads and then almost immediately drop them, frequently frothing at the mouth. I have watched this happen many times, but I have never seen a dog succeed in eating the toad, although some are quite persistent in trying. If a dog were to be successful, it would be quite unhappy a short time later, for in the toad’s warty skin are a large number of glands which secrete a powerful poison. This poison is so irritating to the dog’s mouth that it usually drops the toad immediately. A large dose of this skin poison may be fatal, and there is enough in a single toad either to kill a small dog or make it violently ill. In some species, this poison is considerably more powerful than it is in the common toad.
Indians of South America use the secretion from the skin of a tree frog as a poison for the tips of their arrows, and, although I do not know of any experiments with the substance, a single frog is said to secrete enough to supply fifty arrows. The skin of this tree frog is also used to color the feathers of parrots artificially. Some of the normal green feathers are plucked out and the frog is rubbed over the bird’s skin. When the new feathers grow in, they are yellow instead of green. People have succumbed to the lure of brilliant green and yellow parrot only to find that when the feathers were shed they grew back green instead of yellow.