Florida Tree Frog

Hyla gratiosa Le Conte

Colour: Green or brown of various shades, usually with all upper surfaces distinctly spotted. Sometimes unspotted bright yellow-green. Spots many, more or less rounded, either large or small. Spots may be brown or green of even shade, or light green or brown encircled with darker colour. Legs and arms irregularly banded with dark. Pin spots of bright yellow irregularly placed on the larger spots or between them. Ear brown. Eye bright reddish bronze. Jaw dark, bordered above by white or yellow. This light colour may be continued to the shoulder and sometimes beyond. White or yellow bordered by purplish brown on posterior margin of arm and hand and along posterior edge of foot. Sides may be reticulated with bright yellow. Throat may be purplish brown (female) or bright yellow or green (male). Underparts light, yellowish.
Measurements: Large for a tree frog, i.e. Length 2 to 2 1/2 inches. Head short; 5/8 inch in a frog 2 1/4 inches long. Width between eyes greater than width of eyelid. Ear one-half to two-thirds the diameter of the eye. Legs relatively short; leg to heel equals length of body forward to eye. Tibia shorter than femur.
Structure: Skin thick and leathery, granulated over the whole upper surface as well as on the lower. Head unusually thick through, very short and obtuse anterior to the eyes. A fold of skin over the ear from eye to shoulder; another fold across the breast and one at the base of the throat. Ear round. Hand large; disks on fingers unusually large. Outer fingers slightly webbed. Foot webbed half length of fourth toe. Inner sole tubercle prominent. There is a tarsal fold.
Range: Reported from Georgia, Florida, and Mississippi only. (Riceborough, Ga.; Bay St. Louis, Miss.; Green Cove Springs, Tarpon Springs, Micanopy St. Augustine, Orlando, and Georgiana, Fla.)

Unfortunately, this tree frog has an unusually limited range. It has very rarely been found outside of Florida. It is the largest tree frog of North America, and probably very valuable in the work of destroying noxious insects.

Hyla gratiosa presents a peculiar appearance because of the even granulation of the upper parts. In this characteristic of the skin it differs from all other North American Hylas. All others present a surface either smooth and fine in texture, as in the case of the Green Tree Frog, or one rough with fine warts, as in the Common Tree Frog.

The Florida Tree Frog has colour changes as marvellous as those possessed by most of the Hylas. It may be plain bright green and remain so for months, in fact, one in this phase of colouration was kept for over two years and during this time there was no tendency to become spotted or to turn brown. Also, the brown-spotted phase may likewise endure for months without change. On the other hand, the changes may be very rapid indeed. The tendency for rapid colour change, here as elsewhere among the Hylidae, seems to be at its height when the animals are well-fed, and in the season of greatest activity, that is, in the spring and summer months. At this time the greatest variation in colour may be seen in an individual during the twenty-four hours. It may be bright green with vivid spots, dark at their edges and light in their centres. Gradually (within the space of ten minutes) the spots become more and more obscure until the frog is plain green, very light in tone. Again, within the half-hour the spots reappear, become more distinct, darkening in their centres. The ground colour becomes ashy in the middle of the back; this colour darkens into a mulberry, which colour spreads, obscuring the green. Meanwhile the spots continue to darken until the whole frog is rich brown prominently marked with darker brown spots.

The throat-pouch of the male is very large and is bright yellow or vivid green in colour. When the tree frog is taken suddenly into the hand, this sac is likely to be inflated and the frog gives a harsh-sounding squawk. The voice is unusually harsh and low-pitched.

This Hyla is a curiously artificial-looking frog. If it did not move, we might well think some one's fancy had moulded it out of wax. When it is angry or startled, it fills the lungs, expanding the body until it is nearly as broad as long. It has the slow tendencies of some of the other large tree frogs. It shows a marked desire to cling to one's finger and will not leave, even when the finger is constantly turned so that the tree frog is head down. It will each time clumsily turn around to bring its head uppermost, tuck its toes well under, and settle for a period of contentment and rest.