Pickerel Frog — Part 3

Rana palustris Le Conte

Large tadpoles of the Pickerel Frog have at first sight much the appearance of the Green Frog tadpoles. Looking more closely, we see that the head is much more pointed, the eyes are not widely separated, and the nostrils are close to the end of the muzzle, characteristics which distinguish this species. The younger tadpoles have small roundish spots irregularly placed on a greenish-brown background of body and tail. The dark pigment follows the lines between the muscle-plates of the tail so that for nearly one half its length the tail looks like a black feather. The tail fin is less than one-fourth of an inch wide everywhere. The lateral line organs, especially in the region of the head, are very conspicuous. As soon as the hind legs are well grown, and before the front ones appear, the lines of the lateral folds begin to show, the square spots are blocked out on the back, and the legs become barred with dark. After the appearance of the front legs the swellings in the region of the gills are very noticeable, as are also the lines from the nostrils to the eyes. (1 See Bull Frog, pp. 236, 237.)

Just before the completion of the metamorphosis, while the stump of the tail is still present, and just as the swellings in the gill region disappear, the young frog moults its skin. It now leaves the water and wanders over the grassy places at the margin of the water. It is slender and delicate, and very shy. At our approach it escapes with enormous leaps into the protection of the pickerel weeds and cat-tails that grow in the shallow water.

RANA AREOLATA, B D. AND GIRD. (2 Judging from measurements made on the type specimens in the National Museum, Rana areolata Bd. and Gird. is the same as Rana areolata circulosa Rice and Davis and as Rana areolata capito Le Conte.)

This frog has the hiding instinct thoroughly developed, as has Rana aesopus of Florida. Like the Florida frog also, it has unusually large vocal pouches that can be extended from the shoulder regions. It is a silent, solitary frog, except at the breeding season.

The species can always be distinguished from Rana aesopus, by the lesser development of the jaws in width and massiveness, and because the ratio of head and body measurements are as one to three, instead of one to two and a half.