Among certain of life's improbabilities, like the invention of knitting, is the notion that anyone should ever have looked at a frog and thought to himself, "Yum!" The frog is engaging and lovable—nothing is pleasanter than to see a frog really sitting on a lily pad, blinking his bulgy eyes—but mouth-watering? Well, apparently.
It has been thousands of years now since someone persisted past the frog's uninviting exterior and found him good, thus adding man to the frog's list of foes, which already included water rats, snakes, skunks, birds, turtles, large fish, some leeches, some plant fungi, roundworms, tapeworms and bigger frogs. A female blowfly will lay her eggs in the nostrils of an adult frog and the emerging larvae make their way to the brain and kill him. And boys—"The boys throw stones at frogs in sport, yet the frogs do not die in sport, but in earnest," as Plutarch quoted Bion some time ago.
The frog (the term can include the toad) does not allow this to make him moody. He continues in his astonishing variety, croaking, barking and peeping, making nests in trees, under the ground and on the surface of ponds. He comes in red stripes, and black stripes on gold, in spots and in dark or bright green; he is smooth, lumpy, poisonous or hairy to the touch. He (in the larger sense) incubates his eggs in nests of frog froth, on his own back, in his own mouth and even, in some instances, within the body of the female. There are three viviparous frogs, in Africa, which seem to have been driven to this internal rearrangement by their environment.
Frogs require water, though there are only a few wholly aquatic species (which have been dismissed as large, flabby creatures, scarcely able to creep in shallow water). They occur in all the damp corners of the world except Australia and Antarctica, and if some are scarcely able to creep, others are able to fly.
The life cycle of the tailless amphibians is familiar. There must be very few people who never caught their own tadpoles or, at any rate, had a jar of them in school to watch as they proceeded from tailed raisin to frog. The North American species hatch, with rare exceptions, from eggs to tadpoles, and as tadpoles they are gilled. These gills, external at birth, are internalized as the tadpole grows. Water passes through the tadpole's mouth (which itself has only just developed) and passes out through a hole, the spiracle, in the tadpole's side. A tadpole's mouth is not good for much else than breathing for a time, and he lives on his slowly resorbed tail while he is growing teeth at the other end. The hind legs bud and are coming before the tail goes; when they are relatively well developed, the arms emerge—the skin thins and breaks down, and an arm appears. "It is held that the left arm normally comes out first, but often the right arm appears first," says the Handbook of Frogs and Toads, not getting all unscientifically excited. The function of the internal gills is taken over by the lungs; the eyes are developing, and their two sets of movable lids; the "true frog mouth begins to appear"; the intestine becomes shorter and ready to deal with worms and flies. The froglet begins to hang around the shoreline and the lily pads.
The common North American frogs vary in reaching maturity. They can take from six months to six years. The females are then capable of laying 6,000 to 20,000 eggs. Fertilization completes a process known as amplexus, which may take from eight to 36 hours. When the egg masses are to be laid the male frog grasps the female from behind. He sinks his thumbs into her fat sides and holds on, may one say for dear life? He will not let go until the eggs are laid and fertilized, so both frogs are quite defenseless until it's all over. As the female produces the eggs the male fertilizes them with a cloud of semen, or milt, after which he finally lets go and departs without so much as promising to write. If the eggs haven't been laid in "transient pools, impermanent situations, roadside ditches and temporary floodlands" and don't get eaten by enemies or caught in spring freezes, they will hatch into tadpoles and turn into froglets and then into frogs, and so on.
It is during the breeding seasons, of course, that the male frogs are so exceedingly vocal, though they have noises to be made also for wet weather, dry weather, hot spells, periods of cold and "distress from teasing, alarm, injury or capture." The range of the frog and toad voices from species to species and within a given species is tremendous. The Handbook of Frogs and Toads lists some of the adjectives that have been applied to the voice of the American frog: "bubbling, weird, plaintive, hoarse, woeful, mournful, complaining, nasal, incessant, musical, pleasant, whistling, prolonged, mellow, tremulous, squawking, shrill, deafening, ventriloquial, peeping, metallic, resonant, twittering, loud, guttural, snoring, snorting, gurgling, clacking, explosive, grating and sweet." Most of these represent subjective impressions, but deafening isn't peeping, a squawk is not a gurgle and grating is certainly not sweet. It is agreed that the cry of a frog or toad in peril is a terrifying sound. It has been called "the mercy cry" and can be made by females as well as males. "Let anyone pick up a female solitary spadefoot," the Handbook says, "and squeeze it, and he might think he had a male.... Or lay this same female on her back and stroke her belly, and she will speak vigorously...." Well, no wonder. But the enormous vocal sacs of some species are exclusively the property of the male, and throat coloring is a reliable secondary sex characteristic in some instances.
All frogs have one thing in common: good appetites. Dr. James A. Oliver, director of the American Museum of Natural History, has said that they have an almost unlimited capacity for food (in a caption under a picture of a Neotropical Giant Toad contemplating an enormous dish of worms) but they are primarily insectivorous. This makes the frog a friend to man, who throws rocks at him while he is thus engaged in putting off the day when the bugs take over.
Frogs and toads will eat only live food, which is one reason advanced for the delicacy of the frog's flesh. Nobody advances any recommendations for the toad's flesh, however. No one eats the toad, except some aborigines under considerable pressure of hunger. The skin is poisonous and, the toad's habits being more sedentary than the frog's, his legs are not developed to any appealing degree. Only Shakespeare seems to have given him any real consideration for the pot, and at that the recipe calls for eye of newt, wool of bat, Turk's nose, goat's gall and a lot of other things you'd have to go out for, just to brisk up the toad.
But it is as food or as a laboratory animal that man finds the frog of direct commercial use. Thousands of frogs a year are used in pregnancy tests, which do them no harm and after which they are as good as new, and in physiology classes, which do them lots of harm and after which they are no good at all. These frogs are caught and shipped on this continent. Frogs which are to be eaten are also preferably caught on this continent, but killed and shipped dressed. Restaurants are less ready than labs to set up froggeries, so they are at the mercy of the season, a dry spell or the free-lance froggers' having left off frogging to take up jobs in town.