Rana virgatipes
carpenter frog

Carpenter frogs are found in the Atlantic coastal plain of North America, from the Pine Barrens of New Jersey to the Okefenokee Swamp region of southern Georgia and northernmost Florida. Their range extends farther inland in southern North Carolina and in South Carolina. (Conana, 1975; Hammerson, 2004; White and White, 2002)

Carpenter frogs live in a variety of habitats which contain still or slow moving water and an abundance of aquatic vegetation. They can be found in Delmarva bays, sphagnum bogs, flooded cranberry bogs, artificial lakes, and pine barren ponds. They prosper in wetlands with acidity levels exceeding the threshold for other members of the genus Rana. In areas where pig frogs (Rana grylio) are present carpenter frogs may be present in lower abundance. In northern Florida carpenter frogs can be found in cypress dome and gum swamps, the only area they are found in that state. It is said that carpenter frogs are found in waterways that are tea or coffee colored, where they can easily be camouflaged. Carpenter frogs are often seen completely out of water but never at a large distance from water. They depend on aquatic vegetation in shallow waters for protection and breeding. ("Conservation Plans for Biotic Regions in Florida Containing Multiple Rare or Declining Wildlife Taxa", 2003; Alden and Cassie, 1999; Conana, 1975; Gosner and Black, 1957; Hammerson, 2004; Reshetiloff, 1994; White and White, 2002)

Carpenter frogs are medium sized frogs ranging from 4.1 to 6.6 cm (1.6 to 2.6 inches). They have a brown head, body and legs. Male carpenter frogs have a narrower head than females. There are four distinct yellowish or golden brown stripes that run down the back and sides of these frogs. Two of the stripes run closer to the centerline of the body, while the second two are more lateral. Carpenter frogs are unique in that they have no dorsolateral folds and the webbing of their feet does not reach the longest toe. The underside is cream to yellow in color with dark mottling that is present in no particular pattern. Mottling patterns are often black. A light line is present on their upper lip. Carpenter frogs have paired throat pouches which are spherical when inflated. (Behler and King, 1979; White and White, 2002)

Carpenter frog tadpoles are large, growing up to 9 cm in length. Like their adult counterparts they are brown, with a white speckled underbody. The tail has dark stripes formed from prominent lines of dark spots which run longitudinally through the musculature. The spots will most often fuse to form dark stripes. (White and White, 2002)

Carpenter frogs can be confused with northern green frogs (Rana clamitans), young American bullfrogs (Rana catesbeiana), dark southern leopard frogs (Rana sphenocephala) and young pig frogs (Rana grylio). Northern green frogs and young American bullfrogs lack the yellowish or golden brown stripes present on carpenter frogs. Dark southern leopard frogs have a light spot in the middle of their tympanum, which carpenter frogs lack. Southern leopard frogs lack two of the four stripes present on carpenter frogs. Young pig frogs have pale dorsolateral stripes which sometimes may be unseen at first glance. Their toes are webbed almost to their tips, which is not the case in carpenter frogs. (Conana, 1975; White and White, 2002)

Carpenter frog eggs will hatch approximately one week after laying, depending on water temperature. Tadpoles will live in that state for roughly one year, growing up to 9 cm. They spend the winter in breeding ponds. Between August and September of the following year carpenter frog tadpoles will metamorphose into juveniles. (White and White, 2002)

The longest lifespan documented in captivity was 6 years and 2 months. Wild lifespans carpenter frogs have not been documented. (Snider and Bowler, 1992)

Carpenter frogs are described as a secretive species. They are often difficult to see or capture due to their natural camouflage and shy behavior. When frightened they quickly dart away underwater and raise their head after a very brief period to reevaluate the situation and surroundings. They will usually only have their head exposed during these times.

Carpenter frogs are nocturnal animals. They aggregate in large numbers in suitable habitat. (Conana, 1975; White and White, 2002)

Home Range

Carpenter frogs are found near wetlands throughout the year. While they are most often seen completely out of water they are never far from a water source. (Conana, 1975; White and White, 2002)

Carpenter frogs were assigned their common name based upon their hammering call. When carpenter frogs are calling in a chorus it is often described as sounding like a crew of workmen hammering. When an individual carpenter frog is calling it is described as sounding like two carpenters hammering nails one fraction of a second after each other. While most people have said that the call is “pu-tunk, pu-tunk, pu-tunk.” Males are capable of emitting the call ten times in succession. (Alden and Cassie, 1999; Behler and King, 1979; Conana, 1975; Given, 1987)

Given (1987) demonstrated that carpenter frogs have five other less identifiable calls. Three of which are for aggressive purposes, one release call used when males accidentally grab each other, and one chirp call used by females for courtship. Given (1999) also found that when males call in aggressive situations, they will follow those calls with an advertisement call for attracting females. When they appear to still in be in aggressive situations following the initial call they will adjust their advertisement call to a more aggressive sounding call while still including the necessary components to attract females. (Given, 1987; Given, 1999)

Carpenter frogs also communicate with each other through their breeding practices. Males communicate with the females by displaying their upright posture and combating with other males. (White and White, 2002)

Carpenter frogs forage on the ground and in vegetation for small insects and other small invertebrates. (Conana, 1975; White and White, 2002)

While there is little published information pertaining to natural predators of carpenter frogs, some research suggests that water snakes (Nerodia) eat carpenter frogs. Zampella and Bunnell (2000) suggest that the presence of American bullfrogs (Rana catesbeiana) negatively affects carpenter frog populations. When pig frogs (Rana grylio) are present there has also been a noticeable absence or decline in carpenter frog populations. Carpenter frogs are well camouflaged in their natural habitats. (Conana, 1975; Zampella and Bunnell, 2000)

Carpenter frogs co-occur with green frogs (Rana clamitans), southern leopard frogs (Rana sphenocephala), and Pine Barren treefrogs (Hyla andersonii). (Conana, 1975; Gosner and Black, 1957; White and White, 2002; Zampella and Bunnell, 2000)

There are no known adverse effects of carpenter frogs on humans.

Like most frogs, carpenter frogs consume insects that may be considered a nuisance.

According to the 2006 ICUN Redlist, carpenter frogs are of Least Concern. Conservation status varies locally in the United States. In New Jersey, Delaware, and some areas of Virginia they are protected, while in Maryland and other areas of Virginia they are listed as a species of special concern. ("An Introduction to Mid-Atlantic Seasonal Pools", 2005; Hammerson, 2004; Hammerson, 2006)

Knowing that carpenter frogs thrive in acidic waters it is thought that the neutralization of wetland areas in the Delmarva region may be the cause of their decline in that region. As wetlands become less acidic a larger variety of frogs can inhabit the area including more aggressive species such as northern green frogs (Rana clamitans). Historically populations of carpenter frogs have been found in Kent and Sussex County in Delaware, and Queen Anne’s, Talbot, Caroline, Dorchester, Wicomico, and Worcester counties in Maryland. In the 1990s the carpenter frog population in Talbot County was found to be severely decreased as a possible result of habitat degradation. (Given, 1999; White and White, 2002)

Areas farther south like Georgia the Carpenter Frog is considered common. However it does have a limited range. Considering that the Carpenter Frog requires wetland areas with large amounts of submerged vegetation for breeding, human disturbances to such environments have and will continue to impact the species. ("Conservation Plans for Biotic Regions in Florida Containing Multiple Rare or Declining Wildlife Taxa", 2003)