The state of Alabama shows great variety in its geology and geography, with habitats including mountains, coastal plains, prairies, forests, and valleys. With a temperate climate and abundant rainfall, it provides the perfect location for an abundance of life to flourish and ranks fifth in terms of overall biodiversity among all of the states.
As well as a great variety of birds, mammals, reptiles, and insects, Alabama hosts large numbers of amphibians, including many species of frog. Both treefrogs, Hylidae, and true frogs, Ranidae, reside there, with different species to suit each available habitat type.
Alabama Frogs
1) Northern cricket frog (Acris crepitans)
- Native to the US and northeastern Mexico
- Family: Hylidae
- Order: Anura
- Conservation status: Least concern
The northern cricket frog can be found throughout Alabama, although it is most common above the Fall Line Hills and on the Coastal Plain. It is a small frog, with a maximum length of around 4 cm (1.6 in), and is highly camouflaged, with a combination of grey, green, and brown on the back, and a paler belly. There is also a dark triangle on top of the head, between the eyes.
This species is diurnal and occupies ponds or streams that receive plenty of sunlight and have moderate amounts of vegetation. They are insectivorous, typically eating around twenty insects per day, and have a number of natural predators in Alabama, including the American bullfrog.
Although Alabama populations of the northern cricket frog appear stable, in some areas they are threatened. A study has shown that this species is susceptible to the use of insecticides, and this has the potential to drastically reduce its survival.
2) Spring peeper (Pseudacris crucifer)
- Native to southeastern Canada and the eastern US
- Family: Hylidae
- Order: Anura
- Conservation status: Least concern
The spring peeper has a maximum length of 4 cm (1.6 in) and is brown in color, with a distinctive dark ‘X’ on its back. Despite being common, they are rarely seen due to being so well camouflaged among the woodlands and ponds they occupy – although during spring they most definitely can be heard, with males booming their mating chorus.
This species is nocturnal, a lifestyle that enables it to hide from diurnal predators. Its diet consists of various small invertebrates, with beetles, ants, and spiders being the most popular. Spring peepers breed between January and April; the eggs adhere to aquatic vegetation and take around two weeks to hatch. It is a further three months before the tadpoles undergo metamorphosis.
The chorus the males produce during the breeding season provides females with vital information, so that the female can select the fittest mate to reproduce with. A study found that females prefer loud, low-frequency calls with a high repetition rate – these factors may communicate features of the male, such as longevity, that would be desirable.
3) Barking treefrog (Hyla gratiosa)
- Endemic to the southeastern US
- Family: Hylidae
- Order: Anura
- Conservation status: Least concern
Hyla gratiosa is large for a treefrog, reaching lengths of over 4.4 cm (2 inches). They are bright green in color, with dark spots down the back, and are often confused with squirrel or green treefrogs. One distinguishing feature that can be used to identify them is the occurrence of more granular skin than in either of these other species. They also have a distinctive white line traveling from the lip, down each side of the body.
Barking treefrogs are found throughout Alabama, although are most common on the Coastal Plain where they occupy open woodland and ponds. In the summer they are usually in the treetops, whereas during extreme temperatures they seek refuge by burrowing into sandy soils. This species feeds nocturnally on worms and insects.
As the name suggests, the call of the barking treefrog can, from a distance, sound like a barking dog. As well as using the chorus to select a suitable mate, the females also use the males’ calls to locate them – which is why males arrive at the breeding site earlier than females each evening.
4) Dusky gopher frog (Lithobates sevosus)
- Native to the Atlantic Coastal Plain
- Family: Ranidae
- Order: Anura
- Conservation status: Endangered
Dusky gopher frogs reach around 7 – 11 cm in length (2.8 – 4.3 in) and are green or grey, with a dark mottled pattern covering the body and head. The female is usually larger than the male, reflecting the resources she puts into producing offspring – she must be able to produce and carry large masses of eggs.
This species prefers longleaf pine forests and is found on the Coastal Plain in Alabama. Several of the known dusky gopher frog breeding ponds in Alabama have been drained or destroyed by construction, contributing to population declines. Other factors affecting this species include off-road vehicles damaging wetland habitat, changes in water temperature and rainfall, and the introduction of predators such as fish.
Reducing fragmentation of habitat and prescribed fires have been suggested as conservation strategies for dusky gopher frogs, however fires should only take place after May, as this will reduce the number of individuals lost during the burn.
5) Gopher frog (Lithobates capito)
- Endemic to the southeastern US
- Family: Ranidae
- Order: Anura
- Conservation status: Vulnerable
Lithobates capito is closely related to Lithobates sevosus and has only recently been considered a separate species. The only population known in Alabama is located at the mouth of Dog River, although its typical habitat preferences are similar to that of the dusky gopher frog.
The gopher frog is very similar in appearance to the dusky gopher frog, although the skin is usually lighter in color, with reduced mottling. However, there can be great variation in the coloration of both species, so care should be taken when identifying individuals in the field.
This species is very elusive and spends its days hiding in burrows of mammals or gopher tortoises, emerging at night to predate on insects. Adults congregate at temporary bodies of water to breed between February and March, with females producing several hundred eggs at a time. Environmental factors may often lead to failed breeding, so some conservation efforts have focused on ‘assisted reproduction technologies’ to boost populations and supply young frogs for release.
6) Little grass frog (Pseudacris ocularis)
- Endemic to the southeastern US
- Family: Hylidae
- Order: Anura
- Conservation status: Least concern
The little grass frog is the smallest frog species in North America, with a maximum length of just 1.9 cm (0.75 in), and is pale brown, although some individuals have a green or pink tinge to their skin. Another distinctive feature of this frog is the dark stripe that passes from the snout to the eyes, and down the sides of the body.
Despite having an overall conservation status of ‘least concern’, the little grass frog has declined considerably in Alabama and is only known of in a few locations – many of which are privately owned land, making conservation strategies difficult to implement.
A study into the diet of little grass frogs found that much of their diet consisted of organisms found within leaf litter and soil; this included collembolans, hymenopterans, and acarines. Interestingly, although smaller invertebrates such as springtails or mites may be easier to catch, the researchers suggest that predating on larger invertebrates when available would be more energetically worthwhile – and the feeding patterns they discovered confirmed this.
7) Cope’s gray treefrog (Hyla chrysoscelis)
- Native to the eastern US
- Family: Hylidae
- Order: Anura
- Conservation status: Least concern
Cope’s gray treefrog displays exceptional camouflage, being gray or green in color to blend in with tree trunks – this pattern varies depending on the environment the individual resides in. Typically between 3.2 – 5.1 cm (1.26 – 2 in) in length, this species is sexually dimorphic, with the male displaying a black throat during breeding season, while females’ throats are grey. The frogs also have yellow patches on their hind legs, which are thought to startle predators, although there does not yet appear to be any research into this.
Hyla chrysoscelis is found throughout most of Alabama, although has a preference for deciduous forests, where it feeds nocturnally on moths, spiders, and occasionally other smaller treefrogs. A study into breeding site selection found that this species preferred wetlands within close proximity to wooded areas.
Cope’s gray treefrogs have been found to be naturally freeze-tolerant – an experiment found that they were able to recover even after being frozen solid, an adaptation that may enable them to survive harsh winter conditions.
8) Bird-voiced treefrog (Hyla avivoca)
- Native to the southeastern US
- Family: Hylidae
- Order: Anura
- Conservation status: Least concern
The color of the bird-voiced treefrog can change depending on activity levels and temperature, varying from pale grey or brown, to pale green. With a maximum length of 5 cm (2 in), it is a fairly small frog, although what it lacks in size it makes up for with its loud, bird-like call.
Hyla avivoca is limited to the Coastal Plain in Alabama, although there are unverified reports of a population further north. While it is very similar to the gray treefrog and Cope’s gray treefrog, its smaller size and more slender build enable it to be identified fairly easily in the field.
The most striking feature of the bird-voiced treefrog is, as the name suggests, its voice. Males compete for mates by striking up a whistling chorus, and it has been shown that they will call for longer if they are surrounded by male conspecifics. Females select their mate based on these calls.
9) River frog (Lithobates heckscheri)
- Endemic to the southeastern US
- Family: Ranidae
- Order: Anura
- Conservation status: Least concern
River frogs can attain lengths of 8 – 12 cm (3.1 – 4.7 in) and are dark brown, gray, or olive-colored with rough, textured skin. The underside displays a white mottled pattern, increasing towards the hind legs. This species resides in floodplains, rivers, and streams, where it feeds on invertebrates, mainly insects, but also the occasional other small frog.
While the overall population of the river frog is stable, in Alabama it is a high conservation concern. The main contributing factor to this is the loss of suitable habitat, although this hasn’t presented a problem across much of its range thus far, and much of its range in other states is across protected areas, so it will likely continue to thrive in these regions.
Lithobates heckscheri has evolved a number of anti-predator mechanisms, such as ‘playing dead’ and secreting noxious substances onto its attacker. Tadpoles of the river frog will school, a phenomenon not commonly seen in Ranidae; it is thought that this is to provide greater protection from predators.
10) Pine Barrens treefrog (Dryophytes andersonii)
- Native to the eastern US
- Family: Hylidae
- Order: Anura
- Conservation status: Near threatened
The Pine Barrens treefrog is around 3.8 cm (1.5 in) in length and has a bright green back, separated from its purple-brown sides by a thin yellow line. This species is sexually dimorphic, with females being slightly larger than males. Their call is high-pitched and repetitive, described as a ‘quanking’ sound.
The range of the Pine Barrens treefrog in Alabama is limited to Covington, Escambia, and Geneva counties. The preferred habitat of this species is longleaf pine forests, where the treefrogs feed on ants and beetles. Longleaf pine forests tend to be strewn with small ephemeral pools, which provide breeding habitats.
Contributing factors to the decline of this species include habitat loss and fragmentation, which have resulted in a loss of genetic diversity within populations. Another factor cited to have affected populations is the control of wildfires; while this has been done to improve human health and safety, longleaf pine forests rely on burning to germinate certain seeds and clear excess undergrowth.
11) Green treefrog (Hyla cinerea)
- Native to the southeastern US, from Florida to Virginia
- Family: Hylidae
- Order: Anura
- Conservation status: Least concern
The green treefrog is a fairly large member of Hylidae, reaching lengths of 3.2 – 6.4 cm (1.26 – 2.5 in), and has a fairly slender build with long legs. It has smooth, bright green skin, and a pale stripe traveling from the mouth down the sides of the body. Some individuals also have yellow spots on their backs. These frogs can change color depending on temperature and light conditions, a strategy thought to have evolved for predator avoidance.
Hyla cinerea is found throughout Alabama, although is excluded from areas of the Interior Plateau and parts of the southwestern Appalachians. This species resides in swamps or the edges of lakes and streams, where it perches on vegetation by day, and at night feeds on insects and arthropods. Individuals have been seen pursuing the abundance of insects around artificial lights near houses.
The green treefrog has a distinctive call that can sound like a bell from a distance, thus earning them the alternative name ‘cowbell frog’. The calls show geographic variation, being slightly altered across different regions, although calls may also vary depending on the size of the individual and their body temperature.
12) Squirrel treefrog (Hyla squirella)
- Native to the Coastal Plains of the southeastern US
- Family: Hylidae
- Order: Anura
- Conservation status: Least concern
The squirrel treefrog is small, usually less than 5 cm (2 in) long, although it is characterized by large toe pads to aid climbing. Similar to the green treefrog, squirrel treefrogs can vary their color to camouflage themselves, with skin colors varying from brown to yellow, to green. This can make them difficult to identify: look for a white line on the upper jaw as a tell-tale feature.
Hyla squirella shows great adaptability in habitat choice and, as well as being found in woodlands and riparian zones, is often seen around buildings and in gardens. It feeds nocturnally on small invertebrates, particularly insects, and research has shown that this species can visually detect prey in extremely low light conditions.
Although squirrel treefrog populations are stable, they are at risk of being hit by cars, as during heavy rainfall they often move onto roads. Tadpoles are susceptible to predation by dragonfly nymphs and newts, while adults may be targeted by snakes and birds.
13) Appalachian mountain chorus frog (Pseudacris brachyphona)
- Endemic to the central Appalachian Mountains
- Family: Hylidae
- Order: Anura
- Conservation status: Least concern
Appalachian mountain chorus frogs are usually between 2.5 – 3.2 cm (1 – 1.3 in) in length, and have stocky gray or olive-colored bodies, with white undersides. Males can be distinguished from females by their darker throats, and both sexes display yellow on their legs, which is concealed until the frog moves.
This species is found north of the Fall Line Hills in Alabama and is rarely found on the Coastal Plain. It occupies a wide range of habitats, including temperate forests, rivers, swamps, marshes, and ponds, although it does show a preference for wooded areas. Appalachian mountain chorus frogs predate on a variety of terrestrial invertebrates, including but not limited to beetles, leafhoppers, and earthworms.
Comparatively little is known about Pseudacris brachyphona; it is a highly secretive species and there is limited research into its ecology. The best time to see one is during breeding season (between March and May) when they gather at small ponds.
14) Upland chorus frog (Pseudacris feriarum)
- Native to the eastern US
- Family: Hylidae
- Order: Anura
- Conservation status: Least concern
Upland chorus frogs range from 1.9 – 3.5 cm long (0.75 – 1.4 in) and are brown or gray in color, with a dark stripe running from the snout to the eye and down the sides of the body. Their ventral region is pale cream, although they may show darker mottled patterns across the chest.
These frogs are found throughout much of Alabama down to the Red Hills regions, and east of the Conecuh River. Their preferred habitat includes grassy areas, damp woodlands, and marshes, where they forage for insects by night. Similar to Pseudacris brachyphona, despite being common they are rarely seen.
Breeding in upland chorus frogs takes place between December and April; males select temporary pools to sit in and call – their voice has been likened to the sound of fingers running along a comb. The females arrive and may lay up to 1,000 eggs, which adhere to vegetation and hatch within 3 – 4 days.
15) American bullfrog (Lithobates catesbeianus)
- Native to eastern North America
- Family: Ranidae
- Order: Anura
- Conservation status: Least concerned
As the largest frog species in North America, the American bullfrog is easily recognizable. With lengths from 9 – 15 cm (3.5 – 6 in), they are very distinctive, with green skin over the back and body, and white ventral regions. This species is sexually dimorphic: males and females can be distinguished by the size of the tympana (these being larger than the eyes in males), body size, and the color of the throat (males having a yellow throat).
American bullfrogs are abundant and frequently seen in Alabama, and show great adaptability in habitat selection, occupying lakes, swamps, brackish water, and ditches, usually favoring warm areas with slow-moving water. They are fierce predators and will tackle an enormous variety of prey, such as rodents, crayfish, and snakes. Attracted by movement, they lash out at their target with their strong tongue, which draws the prey back into the bullfrog’s jaws.
Additionally, this species provides a valuable food source for many birds, otters, and predatory fish, although interestingly the tadpoles are avoided by many species due to their unpleasant taste. American bullfrogs are also pursued as a game species, with just the legs being eaten in most cases.
16) Pig frog (Lithobates grylio)
- Native to Florida, the Coastal Plain of southern Georgia, and southeastern South Carolina
- Family: Ranidae
- Order: Anura
- Conservation status: Least concern
Pig frogs are large, with typical lengths of 7.6 – 15.2 cm (3 – 6 in). They have green backs with brown mottling, while their underside is paler with dark blotches. This species shares various morphological similarities to the American bullfrog, leading to the two often being confused: one way to discriminate between the two is to examine the hind toes. The hind toes of the pig frog are all webbed, whereas bullfrogs do not have webbing extending to the tip of the longest toe.
Lithobates grylio occupies well-vegetated areas of pools, marshes, and swamps, where it feeds opportunistically on lizards, insects, and other amphibians. A nocturnal species, the pig frog is especially active during the warmer months and can often be heard calling, having earned its common name due to its ‘grunt-like’ call.
Eggs are laid over vegetation, and while they take just a few days to hatch, juveniles exist in the tadpole state for up to a year before undergoing metamorphosis. Juvenile frogs are more bronze in color than adults.
17) Pickerel frog (Lithobates palustris)
- Native to southern Canada and the eastern US
- Family: Ranidae
- Order: Anura
- Conservation status: Least concern
Pickerel frogs are moderately large, with lengths between 5.7 – 10 cm (2.2 – 4 in), and are pale brown or gray, with distinctive square dark patches in two rows down the back, described as appearing ‘hand drawn’. This feature makes them easily identifiable, although other points to note are the concealed patches of yellow on the hind legs, and the white belly and chest.
The distribution of this species in Alabama is mainly north of the Fall Line, although it may also be found in some regions of the Coastal Plain. With a preference for cool water, it is often found in caves or abandoned mines and only travels to warmer waters during breeding season.
The coloration of the pickerel frog has been suggested to play a role in deterring predators, serving as a warning signal that the frog is poisonous. When under threat, individuals secrete chemicals, which are toxic to certain predators and will irritate human skin.
18) Southern leopard frog (Lithobates sphenocephalus)
- Native to the eastern US
- Family: Ranidae
- Order: Anura
- Conservation status: Least concern
Aptly named, southern leopard frogs have green skin covered with dark spots. The typical length of this species ranges from 5 – 12.7 cm (2 – 5 in), and it has a number of distinctive features, such as a pale spot in the middle of the tympanum and a pale line along the upper jaw.
This species is common and is found wherever there is suitable habitat in Alabama, preferring wetlands with few fish. It has a predominantly terrestrial lifestyle, tending to be found close to water rather than in it. Active during daytime and night-time, southern leopard frogs consume a variety of small invertebrates, and in turn, are predated on by fish, raccoons, and skunks.
The southern leopard frog breeds all year round, and males produce a mating trill from shallow water or a perch by the water’s edge. Research has found that the presence of other calling males actually increases an individual’s testosterone levels, suggesting that the use of social cues may enable this species to coordinate its breeding.
19) Crawfish frog (Lithobates areolatus)
- Native to the central and southern US
- Family: Ranidae
- Order: Anura
- Conservation status: Least concerned
The crawfish frog has not long been known as a frog species present in Alabama, having only been discovered there for the first time in 2016. Ranging in length from 5.7 – 7.6 cm (2.24 – 3 in), it has a stout body with an intricate pattern of dark spots encircled by paler borders down the back and a pale underside.
Males produce a deep, guttural call, inflating the vocal sacs on either side of the head as they do so, while simultaneously contracting their sides to push air out. Outside of breeding season, individuals spend much of their time hidden in the burrows of other animals – often crayfish burrows. As well as making good places to overwinter, these burrows provide the perfect opportunity for crawfish frogs to ambush the insects, spiders, and crayfish on which they feed.
While the overall conservation status of this species is of least concern, individual populations may be under significant threat from habitat loss. Little is known about the populations of crawfish frogs in Alabama, but conservation strategies have been suggested for use throughout their range in the United States, including maintenance of a buffer of grassland around breeding wetlands, prescribed burning, and reduced soil disturbance.
