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.
Development - Life Cycle: metamorphosis
There are no known adverse effects of carpenter frogs on humans.
Like most frogs, carpenter frogs consume insects that may be considered a nuisance.
Positive Impacts: controls pest population
Carpenter frogs co-occur with green frogs (Lithobates clamitans clamitans), southern leopard frogs (Lithobates sphenocephalus sphenocephalus), and Pine Barren treefrogs (Hyla andersonii).
Carpenter frogs forage on the ground and in vegetation for small insects and other small invertebrates.
Animal Foods: insects; terrestrial non-insect arthropods; mollusks
Primary Diet: carnivore (Insectivore , Eats non-insect arthropods)
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.
Biogeographic Regions: nearctic (Native )
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 (Lithobates 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.
Habitat Regions: temperate ; freshwater
Aquatic Biomes: lakes and ponds; rivers and streams; temporary pools; coastal
Wetlands: marsh ; swamp ; bog
Other Habitat Features: riparian
The longest lifespan documented in captivity was 6 years and 2 months. Wild lifespans carpenter frogs have not been documented.
Range lifespan
Status: captivity: 6.17 (high) years.
Average lifespan
Status: captivity: 6.2 years.
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.
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.
Carpenter frogs can be confused with northern green frogs (Lithobates clamitans clamitans), young American bullfrogs (Lithobates catesbeianus), dark southern leopard frogs (Lithobates sphenocephalus sphenocephalus) and young pig frogs (Lithobates 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.
Range length: 4.1 to 6.6 cm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: sexes shaped differently
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 (Lithobates catesbeianus) negatively affects carpenter frog populations. When pig frogs (Lithobates 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.
Known Predators:
Anti-predator Adaptations: cryptic
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.
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 (Lithobates clamitans 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.
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.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
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.
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.
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.
Communication Channels: visual ; tactile ; acoustic
Other Communication Modes: choruses
Perception Channels: visual ; tactile ; acoustic ; chemical
When breeding season begins male carpenter frogs establish and defend their territories through calls. They select territories in shallow wetlands that consist of both still waters and submerged shrubs. The number of calling sites present in a wetland are directly related to the amount of submerged vegetation present that is suitable for laying eggs.
Through the use of aggressive vocalizations, consisting of three different calls, upright posting displays, and combat practices, male carpenter frogs mark their territory and try to attract the attention of females. Combat practices involve males wrestling for brief periods of time. During the wrestling match the males will interlock their front legs in an amplexus like embrace. This is done by attempting to mount each other. Simultaneously males may make aggressive calls that are growl-like. These activities are used to help draw attention from females.
If females are interested in the male based upon his physical display or calls she will approach the male and sometimes communicate with the male with a chirp like call. This chirp like call is not always noticed in male and female carpenter frog interactions. This particular behavior is more common and unique among Delmarva frog populations. Following male and female interaction, mating may occur.
Mating System: polygynandrous (promiscuous)
Carpenter frogs typically mate and lay their eggs between April and July. Female carpenter frogs will deposit a globular mass consisting of up to 600 eggs. The oblong mass is attached to submerged aquatic vegetation within the male’s territory. Egg masses are not attached to vegetation at a depth greater than 30 cm. Each mass ranges from 75 to 100 mm in diameter. Carpenter frog eggs and embryos have the same level of tolerance to acidic water as do adults. Gosner and Black (1957) demonstrated that at a pH of 3.8 or lower resulted in abnormal development. The same results were found when salinity levels were between 0.15 to 0.30 grams per 100 cc.
Females may lay several egg masses throughout a breeding season. Given (1987) demonstrated that males called on 95% of the nights. As a result, he concluded that males almost continuously call and engage in mating activities throughout the breeding season. Findings also show that calling efforts by smaller males are lower than those of larger males. Smaller males tend to grow more during breeding season.
Breeding interval: Male carpenter frogs call 95% of the nights during breeding season, with females laying eggs 2 to 3 times.
Breeding season: Carpenter frogs breed between April and August.
Range number of offspring: 200 to 600.
Average time to hatching: 1 weeks.
Average age at sexual or reproductive maturity (male): 1 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous
Specific information pertaining to parental care in carpenter frogs has not been documented. However, most species in the genus Rana invest little in parental care after having laid and fertilized eggs.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female)
The carpenter frog (Lithobates virgatipes) is a species of true frog found on coastal plain of the Atlantic coast of the United States between central New Jersey and northeastern Florida.[2]
Carpenter frogs are distinguished by their all brown color with two yellow stripes on each side of the back. Their tail is gray in color and their underside is normally white or yellow. Unlike other frogs the webbing on their toes does not reach the longest toe. Carpenter frogs are recognized by their call which resembles a carpenter hammering, which gives them their name. They have ectothermic, heterothermic and bilateral symmetry. The frog's throat pouch is spherical shaped when inflated. Full grown frogs are medium-sized 4.1-6.6 centimeters.[3]
The carpenter frog is found in the Atlantic coastal plains in the United States.[4] From the pine barrens of New Jersey to the bottom of Georgia, the carpenter frog makes its home. The frog is also found, but not common, in Florida.[5] They are usually found in water and rarely on land.[6] The carpenter frog adapted to be able to live in acidic waters. The frog has been observed in cypress ponds, interdunal swales, tupelo swamps, acid swamps, canals, and is associated with sphagnum mats and other vegetation in coffee-colored waters of pine savanna bogs or ponds.[7] They most commonly are found in relatively acidic water abundant Sphagnum or other vegetation leading to being sometimes referred to "sphagnum frogs."[8] They depend on aquatic vegetation in shallow waters for protection and breeding.[4] It is said that carpenter frogs are found in waterways that are tea or coffee colored, where they can easily be camouflaged.[4]
Carpenter frogs are prolonged breeders with a breeding season between 2–3 months. The breeding season typically occurs with onset of warm weather in late April and continues until late July or early August.[9] Males maintain territories with a median radius of 1 meter and produce mating calls on most nights of the breeding season.[10][11] Intensity of the calls varies according to body size, with smaller males having high pitched calls of lower intensity relative to larger males. Calling activity occurs between sunset and sunrise but peaks near midnight.[9] After mating, females lay globular egg masses of 200-600 eggs attached to underwater vegetation up to 8 inches deep.[12]
Tadpoles hatch from eggs approximately one week after laying, and remain in this state for approximately 1 year. Between August and September, tadpoles will metamorphose into juvenile frogs.[4]
Carpenter frogs eat a majority of aquatic insects and invertebrates such as small crickets, bug larva, and spiders.[13]
One of the main reasons that the carpenter frog has become of special concern is due to its susceptibility to habitat loss and degradation.[14] 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) In South Georgia the Carpenter Frog is considered a common species although it has a limited range. Considering that the Carpenter Frog requires wetland areas with large amounts of submerged vegetation for breeding, human disturbances, such as ditching and urbanization, 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)[4]
Because it is known to thrive in acidic waters, throughout time the neutralization of water, specifically in the Delmarva region, has had a great impact on its decline in population because they are unable to adapt. As wetlands become less acidic, it becomes a new habitat for a larger variety of frogs and other species that can thrive in these conditions. It is suggested that predation also plays a role in the decline of their population. These larger frogs include more aggressive species such as northern green frogs which can potentially be a great threat to the carpenter frog. The presence of American Bullfrogs (Lithobates catesbeianus) and Pig Frogs (Lithobates grylio) have also negatively affected the species. Apart from other frogs becoming a threat to the carpenter frog, some research suggests that water snakes (Nerodia) also prey on the carpenter frog.[4]
The carpenter frog (Lithobates virgatipes) is a species of true frog found on coastal plain of the Atlantic coast of the United States between central New Jersey and northeastern Florida.
