Spring Peeper (Pseudacris crucifer)

Description: Maine's smallest frog is one of 2 tree frogs in the state; the larger one is called the gray treefrog. Adult male peepers are typically 2-3 cm (.8-1.2"); females are a bit larger at 2.7-3.7 cm (1.1-1.5") due to a growth spurt at the end of the second year (Oplinger 1967).Young, newly transformed juveniles are 1.35-1.45 cm (0.52-0.56").

The skin of peepers is generally smooth, in contrast to the rough, warty skin of the gray treefrog. There is great variation in skin color, but usually the back and sides are some shade of brown or gray. No doubt the most distinguishing feature is the dark, imperfect cross or X pattern on the back. This accounts for the species name crucifer which means "one who bears a cross." The venter is plain yellowish or grayish white. The throat of the male is basically yellow, but during the breeding season it turns darker and is flecked with yellow. There is a dark stripe running from the snout to the tympanum and a dark v-shaped bar across the head between the eyes.

The skin color lightens at night; peepers can rapidly darken and lighten to match their background more closely (Kats and VanDragt 1986).The frogs appear to have a preference for settling on dark sites, with their skin changing from light tan to deep, brownish black in 15-45 minutes.

Tadpoles have an orange dorsum with dark spots and a greenish tone, an iridescent creamy venter, and an orange tail with black splotches on the outer edge and a crest that extends along the back. They are about 3 cm long (1.2") and their tail is 1.4-2.1 times their body length.

Voice: The advertisement call is a very simple signal, a loud, bird-like peep, with an average peak pitch of 2,895 Hz (Wilczynski et al. 1984). In a Maine population, the dominant pitch was higher on warmer nights, and, independent of this effect, large males had lower pitches than small males (Sullivan and Hinshaw 1990). One male may call 15-25 times per minute (Wright 1914). Each peep ends with an upward slur. Occasionally, a longer call-a short trill-is emitted when another male is close by (Rosen and Lemon 1974).

Audio: Spring Peeper call (coming soon)