About Pseudacris crucifer (Wied-Neuwied, 1838)
Pseudacris crucifer, commonly known as the spring peeper, is a small frog that typically has a tan, grey, or brown body with a dark cross-shaped marking on its back — this marking gives the species its Latin specific epithet crucifer, which means cross-bearer, though the marking can sometimes be indistinct. Additional dark markings include lines between the eyes and a crossband on the hindlimbs. Adult body length ranges from under 25 mm (0.98 in) to 38 mm (1.5 in), and adult body mass ranges from 3 g (0.11 oz) to 5 g (0.18 oz). Unlike some other species in the Pseudacris genus, P. crucifer does not have white lines on its lips, though its lips may be a lighter shade than the rest of its head. There are two main groups of spring peepers with distinct geographic ranges. The southern spring peeper occupies habitat along the U.S. Gulf Coast, from southeastern Texas to southeastern Georgia and northern Florida. The northern conspecific (member of the same species) is found across all territory east of the Mississippi River in the U.S., extends into Atlantic Canadian provinces, and reaches as far west as Saskatchewan, Canada. Spring peepers live primarily in forests and regenerating woodlands near ephemeral or semipermanent wetlands. They often form breeding aggregations that can number several hundred individuals, and commonly breed in a wide range of wetland types: temporary vernal ponds that dry out over summer, intermediate ponds that alternate between dry and wet periods each year, year-round permanent ponds, swamps, and disturbed human-created habitats such as farm ponds and borrow pits. During the breeding season, spring peepers are found near bodies of water that do not contain fish and are free of pollutants. Breeding choruses form near trees overhanging bushy growth or in secondary forests, and may also be located within ponds, marshes, or swamps. Spring peepers usually resume calling activity during warm rain, and are not commonly seen outside of breeding choruses. In the non-breeding season, they live among dead plant material from trees, shrubs, and other plants in woodland areas. While spring peepers can use multiple pond types for breeding, they are superior competitors in permanent ponds due to their greater ability to resist predation in these environments. As an amphibious species, they require marshes, ponds, or swamps to provide the aquatic environment that their eggs and tadpoles need to develop. In the northern parts of their range, spring peepers regularly experience subfreezing temperatures during the breeding season. The species can tolerate freezing of some of its body fluids, and hibernates under logs or behind loose tree bark. It can survive freezing of internal body fluids at temperatures as low as −8 °C (18 °F). Male spring peeper mating displays are affected by two key environmental factors: humidity and vegetation density. These factors heavily influence the arboreal (tree-dwelling) behavior that spring peepers exhibit during mating. Locations with higher humidity and higher air temperature see more dominant arboreal behavior, suggesting latitude may impact this trait. Spring peepers in warmer areas generally exhibit more arboreal behavior than those in cooler environments. Mating calls from males calling above ground are of better quality than calls from males calling near the ground. Local vegetation also improves calling from arboreal positions compared to lower positions, because lower-level spatial features can interrupt the call. Spring peepers almost always migrate at night, most likely to prevent their bodies from drying out.
