Pseudacris crucifer
Spring Peeper

Pseudacris crucifer is native to eastern North American. It is found from southeast Manitoba east to the Atlantic Ocean, and south to eastern Texas and mainland Florida (but not on the Florida Peninsula). It is reported to have been introduced to Cuba as well. (Conant and Collins, 1998; Skelly, 1996)

This frog is found in marshy woods and non-wooded lowlands near ponds and swamps. Although it is a good climber, spring peepers seem to prefer to be on the ground or hiding in leaf litter. Spring peepers breed in freshwater ponds or pools, and prefer to use ponds where there are no fish. They often use temporary ponds that dry up after the larvae (tadpoles) have transformed into adult frogs and left the water.

One study found that during a drought in Arkansas, spring peepers were one of the most commonly discovered anuran in caves. The authors suggest this species used these caves in late summer (late July/early August) because the relative humidity in the caves was high (avg = 79%). (Blair and Wassersug, 2000; Prather and Briggler, 2001)

The average spring peeper varies in size from 20 - 25 mm at maturity. This frog is usually some shade of brown, gray, or olive, and occasionally may be yellow or reddish. Its belly is cream or white, and it is marked by a dark cross on its back and dark bands on its legs. Pseudacris crucifer has moderately webbed feet and noticeable disks on its fingers and toes. (Hinshaw and Sullivan, 1990)

Eggs are generally laid in temporary ponds. Embryos and larvae may die when the pH of the habitat ranges from 4.2 to 4.5. The larval stage can last from 45 to 90 days, and is partially dependent on the availability of water in vernal pools. Compared to a related species, Pseudacris triseriata, the spring peeper has a longer development time (a prolonged larval period), in which metamorphosis is delayed. (Blair and Wassersug, 2000; Smith and VanBurskirk, 1995; Zampella and Bunnell, 2000)

Males begin mating rituals shortly after the end of hibernation. The males will gather at small pools by the hundreds. Each male establishes a small territory and begins calling quite frequently. This call is described as a shrill "peep peep peep." The louder and faster he peeps, the better his chances of attracting a receptive female. Males usually compete in trios, and the male with the lowest-pitched call usually starts the vocal competition. (Woodward and Mitchell, 1990)

The spring peeper is usually about three years old before it reaches the breeding stage. The species is one of the first anurans to begin breeding after winter hibernation. The breeding period lasts from March - June, when 800 - 1000 eggs per female are laid in shallow ponds. The eggs hatch within 6 to 12 days, and tadpoles transform to adults during July (range 45 - 90 days).

Female spring peepers typically choose mates in a size-selective fashion -- larger males are preferred and are more successful breeders. (Blaustein, et al., 2001; Lance and Wells, 1993)

Females lay eggs that they supply with nourishing yolk, but once they lay their eggs their investment is done. Males provide no parental care or investment, just fertilization. (Skelly, 1996)

The longest known lifespan in wild is unknown. In captivity, peepers will live to 3 - 4 years. (Blaustein, et al., 2001)

Spring peepers are known for their high piping whistle consisting of a single clear note repeated on intervals. The males sing, normally doing so in trios, the one who starts each round is usually the deepest voiced. During the daytime, peepers often call during light rains or in cloudy weather. They are usually silent at the end of summer, but call from forests during the fall.

This species hibernates under logs and in treeholes. (Tyler, 1994)

During breeding season, home range diameters range from 1.2 - 5.5 m (4 - 18 ft.), and the peeper's average daily travel ranges from 6.1 - 39.6 m (20 - 130 ft.). They tend to be found in natural ponds and bogs. (Zampella and Bunnell, 2000)

Mating calls are heard during early April - May, and greatest during warm, wet nights. They start calling when the ambient temperature is 28C. Calls (peeps) often end with a high pitched slur, and is repeated about 20 times/minute. (Blaustein, et al., 2001; Hinshaw and Sullivan, 1990)

Pseudacris crucifer is insectivorous, eating mainly small insects including ants, beetles, flies, and spiders. It is believed that food is chosen more by availability and size than by actual preference.

Subadult peepers are know to feed most often in the early morning hours and in the late afternoon, while adults more often fed in the late afternoon into the early evening hours.

Larvae graze on algae, detritus, and micro-organisms. (Buell and Marshall, 1955; Oplinger, 1967)

Many predators attack adult peepers, including salamanders, owls, large spiders, snakes, and other birds.

Predaceous aquatic invertabrates in vernal pools prey upon the spring peeper tadpole. The invertebrates include the predaceous diving beetle (Family Dytiscidae), leeches (Hirundinea), dragonfly larvae (Odonata) and giant water bugs ( Belastoma spp.). In response to the presence of predators, peepers in larval stage travel short distances in a darting fashion, then remains completely inactive for long bouts of time.

There has been a wealth of work examining tadpole phenotypic plasticity in common frogs like the spring peeper. With their short bodies and deep tails, peepers tend to sacrifice part of their tails during tadpole development. One study found that 62.7% of peeper individuals lost part of their tails during Gosner developmental stages 26-34. The proportion of the tail that was damaged was 8.5%. In later Gosner stages (35 - 43), only 34% of peepers exhibited tail damage, suggesting either that individuals can rehabilitate tails or that injured individuals do not survive to the next stage. However, spring peepers are one of the few species in this study that could tolerate tail loss exceeding 25% (sometimes >50%). (Blair and Wassersug, 2000; Hinshaw and Sullivan, 1990)

The spring peepers' role (as adults) is to feed on insects, which put it in competition with other amphibians as well as different spider species that feed on insects as well. Vernal pond predators such as leeches, large insects, and salamander larvae may depend on the spring peeper as a source of food.

Spring peepers are hosts to parasites, including a protozoan species called Opalina obtrigonoidea. (Blair and Wassersug, 2000; Delvinquier and Desser, 1996)

Spring peepers may help to control certain insect populations. (Blair and Wassersug, 2000)

There are no known adverse effects of Pseudacris crucifer on humans.

This is a relatively common anuran within its range, but some states on the on the edge of its range give it special protection. It is listed as "Protected" in New Jersey and "Threatened" in Kansas. (Levell, 1997)

A recent study examined the effects of climate change on anurans. In the case of the spring peeper, over the last 30 years, overall start of breeding was not significantly earlier. However, the authors did find a positive relationship between temperature and breeding date.

Pseudacris crucifer was formerly known as Pseudacris crucifer, and is referenced as such in older book and article citations. (Blaustein, et al., 2001)