Eastern Frogs and Toads
By A. Hyatt Verrill
Owing to popular prejudice, the frogs and more especially the toads, are the least known and studied of all our common animal neighbors, with the exception of snakes. When this foolish repugnance is overcome, however, and we look more closely at their habits, we are surprised to find what really beautiful and interesting creatures they are. In our northeastern states the true frogs belonging to the genus Rana are represented by five species; the true toads of genus Bufo by one species; the spade-foots, genus Scaphiopus by one species, and the tree frogs, or, as they are more commonly called, "tree toads," by three species, representing the two genera Hyla and Acris.
All the frogs and toads of the United States undergo a gradual metamorphosis through a larval or tadpole state, and when in tadpole form are very difficult to identify.
Our commonest eastern frog is the "green frog" or "spring frog"—Rana clamata. This species is bright green varying to bronzy green above, everywhere spotted with blackish or dusky. Below the color is white or pinkish. This frog is entirely aquatic, never leaving its pond or brook in search of insects but sunning itself upon the bank, from which it leaps into the water at the approach of an intruder, uttering a sharp squeak as it does so. In its habits the green frog is rather solitary, and is not noisy, contenting itself with an occasional nasal "chung!" The tadpoles, like those of the bull frog, take two years to mature.
Our next most common species is the "pickerel frog" or "gray frog," Rana palustris, a brownish gray species, ornamented with four rows of squarish darker spots; below, the color is silvery white with inside of thighs bright yellow. The young are golden green. This species prefers cold brooks and springs, from which it wanders considerable distances in search of insects, and on spring or summer mornings is abundant in grassy fields or meadows some distance from water. It is rather solitary in habits, more than two individuals rarely being seen together. It is a remarkable jumper, frequently leaping eight or ten feet. The note is a prolonged croak, somewhat resembling the sound made by tearing coarse cloth.
The well known "bull frog," Rana catesbiana, is a common species and is the largest of North American frogs, frequently attaining a foot or more in length. The color is greenish above, becoming much brighter on the head, marked with more or less numerous spots of dark brown or black. This frog, whose deep bass notes are so familiar to every dweller in the country, prefers rather large bodies of water and delights in bushy wooded shores, where he can sun himself in comparative safety. When captured, this species frequently utters a loud cry of distress, often screaming steadily for more than a minute. The tadpoles are very large, and as before mentioned require two years to reach maturity. The legs, however, appear the first season and the tadpoles then present a curious appearance, frequently hopping about upon the bottom of brooks or ponds or using their legs as an aid to this tail when swimming.
A very beautiful and in some places abundant species is the "leopard frog," "spotted frog" or "shad frog," Rana halecina. This frog is usually bright clear green above, ornamented with numerous dark spots, each spot bordered with lighter green or yellow. There are also usually two large spots between the eyes and a yellow or pale line along each side of the body. The belly is pearly or yellowish. The leopard frog is the most widely distributed of all our frogs, being found in greater or less abundance from Athabasca Lake to Guatemala, and from the Atlantic coast to the Sierra Nevada Mountains. This frog is fond of swamps and stagnant water, and is usually the first frog heard in spring. In habits it is gregarious, often swarming in immense numbers in comparatively small bodies of water.
Our fifth and last frog is the "brown frog" or "wood frog," Rana sylvatica, a handsome reddish brown species with a dark band on either side of the head. As its name implies this is a woodland species and is seldom seen in the water unless during the breeding season, when it readily enters ponds or streams to deposit its eggs. The wood frog is a prodigious leaper, even excelling the pickerel frog in this respect. Its color so nearly matches the fallen leaves among which it lives that it is very difficult to discern, and apparently aware of this fact it will often remain motionless until almost stepped on.
The spade-foots are a curious genus of frogs half-way between the true frogs and toads. They are represented in the East by the "solitary spade foot," Scaphiopus holbrookii, a dull olive-brown species, readily distinguished by the spur like process on the heel. These creatures spend the greater portions of their lives in shallow burrows in the ground. In the spring they emerge from their holes and repair to the nearest pool or puddle, frequently in immense numbers, where they deposit their eggs. As these puddles are usually of a temporary character the metamorphosis of the tadpole is very rapid, but varies greatly in different localities; in dry places the young lose their tails when very small, whereas in damp or moist situations they retain this appendage until fully grown and burrowing in the ground. During the breeding season, the spade-foots are very noisy, but after this time they become quiet and disappear entirely, and for this reason are often considered much rarer than they are in reality. The burrows of the spade-foots are very shallow, and they depend upon loose earth falling into the holes for concealment. Oftentimes this loose debris barely covers the head of the owner, and the brassy eye peering out of the earth has a very peculiar appearance.
Our common toad, Bufo lentiginosus, is too well known to require any description. The eggs are deposited in shallow ponds or brooks, and are enclosed in long thick-walled tubes of transparent albumen. These tubes lie in long spiral strings on the bottom of the ponds or pools, and in spring may often be found in immense numbers in such situations. The tadpoles reach the adult stage earlier than the frogs and lose the tail when exceedingly small; they are frequently seen in large swarms in early fall as they migrate from the water to higher land. The toad has availed himself of man's inventions in some localities by making nightly visits to the arc-lights, where they sit about complacently waiting for unfortunate light-blinded insects to fall within their reach. Our commonest tree-toad Hyla pickeringii is much oftener heard than seen. In early spring the shrill whistle of these little fellows issues incessantly from every swamp or bog; so loud and penetrating is the sound of their chorus that it can be plainly heard far more than a mile. After the eggs are deposited the Hylas leave the ponds, and ceasing their music spend their time until autumn among the leaves and underbrush of woods. In the fall the little fellows ascend the trees and once more sing to each other among the reddening leaves. This autumn song, however, is much weaker than that of spring and closely resembles the full note of the purple-finch. It is usually the last note of autumn, and is heard until the severe frosts compel the little Hyla to seek shelter beneath the fallen leaves. The color of this Hyla is yellowish brown marked with dusky spots and lines, but always distinguishable by the X-like marking on the back.
Our other Hyla is H. versicolor, a larger and clumsier species than the last The color is very variable and may be either green, brown, gray or almost white, according to the object on which the Hyla is resting. The most common color is a dull gray marked with black or darker brown, and almost exactly matching the lichen-covered branches wherever he delights to repose. The note of this tree-toad is a loud coarse resonant trill, quite closely resembling the sound of a woodpecker rapping on a dead limb. The note is most frequently heard just before or after rain, and is often considered in rural districts as a sure sign of a shower. The eggs are laid in packets on blades of grass or sticks in shallow water, and the metamorphosis takes place when they are very small.
Our third and last tree-toad is Acris gryllus or the "cricket frog," a small handsome species, abundant in the south but rare or casual north of New York. The cricket frog is brownish in color with the middle of back and head bright pea green. There is also a dark triangular patch between the eyes and a whitish line from eye to ear, with three oblique blotches on the side of body. This little fellow loves the muddy borders of ponds or sluggish streams into which he leaps when alarmed. Unlike the Hylas the cricket frog does not conceal himself among leaves or other vegetation and is consequently much more readily seen. They are good swimmers and remarkable leapers, and are altogether a very active creature. The note resembles closely that of a cricket, and is heard most frequently in early spring in the vicinity of swampy ponds and flooded meadows.