California is located on the Pacific Coast in the western United States. This state boasts a broad range of habitats, including coastal marshes, deserts, grasslands, and wetlands, and experiences a temperate climate with warm, dry summers, and mild, wet winters.
A wide variety of frogs can be found within California. Some are non-native species and are considered invasive due to the damage they cause to ecosystems, while others are endemic to the state and can only be found in a handful of locations. Many of California’s native frog species are suffering declines and face threats. Habitat protection and restoration projects within the state are essential to ensure the longevity of these animals.
California Frogs
1) California red-legged frog (Rana draytonii)
- Native to the western US
- Family: Ranidae
- Order: Anura
- Conservation status: Near threatened
The California red-legged frog reaches 3.8 – 12.7 cm (1.5 – 5 in) in length, with females being significantly larger than males. The dorsum of this frog can be brown, gray, or olive, and may have small dark flecks or larger spots. The hind legs and underside are typically red or pink in color.
Historically, the range of Rana draytonii extended along the majority of the Californian coast, however populations are decreasing, and it is likely that this range is now greatly reduced. There are various threats to this species, including urbanization, invasive species, pollution, and droughts.
The preferred habitat of this species is in lowland ponds surrounded by humid forest or grassland – research has indicated that the non-breeding habitat away from these pools is just as essential for these frogs as the pools themselves, which has implications for conservation strategies. Adult California red-legged frogs feed on insects and other invertebrates, whereas tadpoles consume algae.
2) Northern red-legged frog (Rana aurora)
- Native to western North America
- Family: Ranidae
- Order: Anura
- Conservation status: Least concern
The northern red-legged frog attains lengths of 4.4 – 8.4cm (1.7 – 3.3 in). This frog is very similar in appearance to the California red-legged frog, with a brown, gray, or olive-colored dorsum scattered with dark spots or flecks, and red or pink markings on the underside and hind legs. Northern red-legged frogs have prominent dorsolateral folds.
In California, this species can be found in the north of the state, particularly in Mendocino County. Its preferred habitat is humid forest and grassland, and streams surrounded by vegetation – it breeds in permanent water bodies such as ponds or lakes. Northern red-legged frogs consume various invertebrates.
Both adult and larval members of Rana aurora have predator avoidance strategies. Adult individuals have been shown to escape by jumping into the water, where they may burrow into litter or swim a short distance. Tadpoles may undergo metamorphosis early if they detect chemical cues from predators in the water.
3) American bullfrog (Lithobates catesbeianus)
- Native to eastern North America
- Family: Ranidae
- Order: Anura
- Conservation status: Least concern
The American bullfrog is the largest frog in North America, with males reaching 15.2 cm (6 in) in length, while females are slightly larger, growing to 16.2 cm (6.4 in). This species has prominent dorsolateral folds and large tympana, which are bigger in males than females. The coloration is green, and there may be gray or brown patterning across the dorsum, while the underside is pale.
Lithobates catesbeianus has spread throughout most of California, except for in particularly dry areas or regions at higher elevations. As a non-native species, it can cause a significant amount of damage and may compete with native species for resources. Its preferred habitat includes warm, permanent water bodies surrounded by grassland, farmland, or woodland.
American bullfrogs consume a variety of invertebrate species such as beetles, dragonflies, and decapod crustaceans. They will also feed on fish, frogs, snakes, and small mammals, capturing them with a strike of their long tongue.
4) Southern mountain yellow-legged frog (Rana muscosa)
- Endemic to the southern Sierra Nevada and the Transverse Ranges
- Family: Ranidae
- Order: Anura
- Conservation status: Endangered
Southern mountain yellow-legged frogs grow to 5 – 7.6 cm (2 – 3 in) in length, and individuals have a slender build with a slim waist and long hind limbs. The skin is smooth and varies in color – usually olive, yellow, or brown across the dorsum, with darker markings. The underside, including the hind legs, is yellow.
This species was once found in San Bernadino, Los Angeles, Kern, Tulare, Inyo, and Fresno counties in California, however populations are decreasing and have disappeared from much of their former range. It occupies ponds and streams in the mountains, usually in areas with rocky substrates.
Threats to Rana muscosa include the introduction of non-native species, disease, climate change causing adverse weather conditions, and agricultural activities. Conservation efforts are focusing on the restoration and maintenance of habitat, as well as learning more about chytridiomycosis, an infectious disease that is decimating populations.
5) California treefrog (Pseudacris cadaverina)
- Endemic to Pacific and western regions of North America
- Family: Hylidae
- Order: Anura
- Conservation status: Least concern
Male California treefrogs are smaller than females, with individuals reaching 3.6 cm (1.4 in) and 4.5 cm (1.8 in) respectively. This frog has a rounded body shape and short forelimbs. The skin across the dorsum has some protrusions, while on the underside it is typically smoother. Individuals are gray or brown in color above with dark spots, and lighter gray or white on the underside, with yellow on the groin and hindlegs.
Pseudacris cadaverina can be found in southern coastal California, where it occupies rocky streams and permanent pools. The diet of this species includes invertebrates such as spiders, insects, and centipedes. Populations of the California treefrog can be partitioned into three major groups based on their precise location, and research has shown that these groups are diversifying from one another genetically.
6) Foothill yellow-legged frog (Rana boylii)
- Native to Oregon and California
- Family: Ranidae
- Order: Anura
- Conservation status: Near threatened
The foothill yellow-legged frog is a medium-sized frog, reaching 3.8 – 8.1 cm (1.5 – 3.2 in). It has a slender build and long legs, and granulose skin. This frog is gray, brown, olive, or red in coloration, and some individuals may have dark mottling or spots across the dorsum. The underside is usually white, with some dark spotting around the throat and yellow on the hindlegs and lower abdomen.
Historically, Rana boylii had a wide range spanning much of the California coast and along the western side of the Sierra Nevada Mountains. However, disease, pollution, habitat loss, and invasive species have driven this frog into decline and its current range is greatly diminished.
Habitat restoration has been proposed as a conservation strategy, particularly in relation to upland habitats and the flow of rivers and streams. Interrupted flow through water systems has been previously identified as a risk factor for the foothill yellow-legged frog, with dams reducing its reproductive success.
7) Pacific treefrog (Pseudacris regilla)
- Native to Pacific and western regions of North America
- Family: Hylidae
- Order: Anura
- Conservation status: Least concern
The Pacific treefrog grows to just 1.9 – 5.1 cm (0.75 – 2 in) in length and has a very slim waist with long hindlimbs. This species has the remarkable ability to change color to blend in with its surroundings – there are two morphs, green and brown, which can alter the shade of their skin. The underside is pale, with yellow on the hindlimbs.
Pseudacris regilla can be found in the far northern coastal region of California. It resides in a variety of habitats including forest, grassland, caves, pastures, and desert streams, and individuals have been shown to select microhabitats based on their basic skin color.
Pacific treefrogs mate in water, usually between February and July. Females lay between 400 and 750 eggs, which are deposited in smaller masses and adhere to aquatic vegetation, hatching between three and five weeks later.
8) Northern leopard frog (Lithobates pipiens)
- Native to the Nearctic region
- Family: Ranidae
- Order: Anura
- Conservation status: Least concern
The northern leopard frog grows to 5.1 – 11.1 cm (2 – 4.4 in) in length and has a slender build with long legs. Its dorsal coloration is green, tan, or brown, with dark brown spots that resemble those of a leopard. The underside is much paler, usually cream or white, and there may be a white stripe on the upper jaw.
Lithobates pipiens can be found in northern California and may also be found in the northeast, although its exact range is unknown. The preferred habitat of this species is grassland, woodland, lakes, ponds, or canals – it generally selects moister areas with abundant vegetation.
The diet of the northern leopard frog includes leeches, fish, amphibians, snakes, and small birds. This frog has been shown to retract its eyes during swallowing, which may assist the food in traveling down the esophagus.
9) Baja California frog (Pseudacris hypochondriaca)
- Native to Pacific and western regions of North America
- Family: Hylidae
- Order: Anura
- Conservation status: Least concern
The Baja California treefrog is small, growing to 1.9 – 5.1 cm (0.75 – 2 in). It has a large head and a slender waist, and its skin is smooth. The dorsum is typically green or brown, although it may also be tan, gray, or even reddish in color. The underside is usually pale, with yellow on the hindlimbs.
In California, the range of this species covers California City and Soda Springs, although the populations here are likely to have been introduced. It is flexible in terms of habitat, occupying forest, grassland, and desert streams – outside of breeding season, individuals can be found far away from water.
Research has found that populations of Pseudacris hypochondriaca in California are rife with parasitic worms. It is thought that the frogs become infected with these when they visit water, and males and females tend to be affected equally.
10) Sierra Nevada yellow-legged frog (Rana sierrae)
- Endemic to the Sierra Nevada mountains
- Family: Ranidae
- Order: Anura
- Conservation status: Vulnerable
The Sierra Nevada yellow-legged frog is medium-sized, growing to a length of 5 – 7.6 cm (2 – 3 in). Individuals have a slender waist and long legs, and their smooth skin can be olive, yellow, or brown in color. Their underside is typically pale orange or yellow, with this color extending underneath the hindlimbs.
The range of this species has greatly decreased in recent years, with populations still declining due to habitat alteration, invasive species, and disease. These frogs tend to reside at elevations greater than 1,370 m (4,495 ft) and can typically be found in close proximity to mountain streams or lakes.
Rana sierrae has a varied diet, including both terrestrial and aquatic invertebrates, as well as dead frogs and even its own eggs! Throughout the year, populations move between overwintering, breeding, and feeding sites.
11) Columbia spotted frog (Rana luteiventris)
- Native to western North America
- Family: Ranidae
- Order: Anura
- Conservation status: Least concern
The Columbia spotted frog is large, reaching up to 10 cm (4 in) in length with a broad body and relatively short hindlimbs. Its eyes are tilted slightly skywards, a strategy that may aid in predator avoidance. The coloration of this frog can be tan, brown, olive, gray, or rusty red, with dark black spots across the dorsum, while the underside is usually paler.
Rana luteiventris has a somewhat restricted range within California; it can be found on the east side of the Warner Mountains, where populations occupy shallow waters, usually in wetlands or ponds that maintain a consistent temperature and have plenty of emergent vegetation.
During breeding season, mating can become a chaotic affair, with males clambering on females and trying to dislodge their opponents. Male frogs with thicker forearms and larger nuptial pads are generally more successful in reproducing.
12) Cascades frog (Rana cascadae)
- Native to the Cascade Mountains in Washington, Oregon, and California
- Family: Ranidae
- Order: Anura
- Conservation status: Least concern
The Cascades frog reaches 4.4 – 7.5 cm (1.7 – 3 in), with females typically being larger. Individuals have a slender waist and long legs, with pronounced dorsolateral folds. They can be brown, copper, tan, or olive green with dark spots across the back, while the underside is cream-colored.
This species can be found in northern California – it was once found further south; however, it is now extirpated from many areas and continues to decline in others. The habitat preferences of Rana cascadae include lakes, wet meadows, and streams, particularly those with a silty substrate, and those that are fishless.
The main factors contributing to the decline of this species are loss of suitable breeding habitat, invasive predatory fish, and the degradation of foraging habitat such as meadows. Monitoring populations, assigning protection to the species, and captive breeding projects have all been suggested as potential conservation strategies for the Cascades frog.
13) Oregon spotted frog (Rana pretiosa)
- Native to the Pacific Northwest
- Family: Ranidae
- Order: Anura
- Conservation status: Vulnerable
The Oregon spotted frog is sexually dimorphic, with females reaching up to 10.1 cm (4 in) in length, while males don’t grow to more than 7.5 cm (3 in). This frog has a robust build, and its skin is brown, olive green, tan, or reddish across the dorsum, while the underside is a bold red-brown color. There are small black spots on the back, sides, and legs, and the throat is pale gray.
Rana pretiosa can be found in the far northeastern corner of California. It resides in bodies of water amongst coniferous forest – during breeding individuals occupy areas with sedges or rushes, and during winter they bury themselves in vegetation underneath the ice.
Threats to this species include road construction, invasive species, pollution, and disease. Although the Oregon spotted frog has declined quite dramatically in recent years, a recovery plan is in place, providing hope for the future.
14) Sierran chorus frog (Pseudacris sierra)
- Native to California, Idaho, Oregon, Nevada, and Montana
- Family: Hylidae
- Order: Anura
- Conservation status: Least concern
The Sierran chorus frog, also known as the Sierran treefrog, reaches 1.9 – 5.1 cm (0.75 – 2 in) in length and has a large head with big eyes. The dorsal coloration varies – it can be green, tan, brown, gray, or cream – while the underside is always pale in color, with yellow on the hindlimbs.
Pseudacris sierra can be found throughout the northern portion of California, and is very flexible in terms of habitat – populations can be found in mountains, forests, grasslands, and farmland. Despite being treefrogs, individuals spend much of their time in vegetation close to the ground.
Although populations of the Sierran chorus frog are stable, they may be adversely affected by invasive species or diseases. Certain types of insecticide have also been shown to decrease body size and survival in this species.
15) African clawed frog (Xenopus laevis)
- Native to eastern and southern Africa
- Family: Pipidae
- Order: Anura
- Conservation status: Least concern
The African clawed frog is large, reaching 5.1 – 14.3 cm (2 – 5.6 in) in length. It has a bulky body and a small head with upturned eyes. The smooth skin is olive or brown in color, with some dark markings across the dorsum, while the underside is white with occasional spots.
Xenopus laevis is an invasive species in California, where it can be found in the south of the state along the coast. Individuals will reside in a variety of aquatic habitats, and are highly adaptable, although they prefer areas with plenty of vegetation. They are voracious predators and will consume anything they can capture, including invertebrates, fish, and other amphibians.
Due to the extreme damage that this species can cause to ecosystems in California, it is prohibited to possess or transport it within the state without a permit. African clawed frogs are not isolated individuals in California – breeding populations are present in the state, and there is every chance of them spreading.
16) Southern leopard frog (Lithobates sphenocephalus)
- Native to the eastern US
- Family: Ranidae
- Order: Anura
- Conservation status: Least concern
The southern leopard frog can grow up to 12.7 cm (5 in) in length, although is more typically found to be around 5.1 – 9 cm (2 – 3.5 in). It has a slender build with prominent dorsolateral folds and long legs. The background color of this frog is brown or green, and it has dark spots across the dorsum which are surrounded by a paler outline. The legs are usually striped.
Lithobates sphenocephalus is thought to have been introduced to California in the early 1900s. It can be found in the Prado Flood Control Basin and in Madera County, where it occupies shallow waters such as streams, ponds, and canals. This species feeds on a variety of invertebrates, including crayfish.
It is likely that the larvae of southern leopard frogs were introduced to California accidentally, when bullfrogs, mosquitofish, and Louisiana red swamp crayfish were brought in to be purposefully released.
17) Rio Grande leopard frog (Lithobates berlandieri)
- Native to the southern US
- Family: Ranidae
- Order: Anura
- Conservation status: Least concern
The Rio Grande leopard frog is fairly large, growing to 5.6 – 11.2 cm (2.2 – 4.4 in). This frog has distinct dorsolateral folds, and males can be distinguished from females by their external vocal sacs. The dorsum is gray, green, or brown with many dark spots, while the underside is cream, with some yellow on the hindlimbs.
This species can be found in the far southeast of California – it will occupy a wide variety of aquatic habitat, from streams and ponds to cattle tanks and wells. Lithobates berlandieri is an opportunistic feeder, consuming an enormous variety of invertebrates such as beetles and spiders.
