Pacific Tree Frog (Pseudacris regilla), also known as the Pacific Chorus Frog.
Order: Anura; Family: Hylidae; Genus: Pseudacris. Like other Hylids, it possesses adhesive toe pads for climbing, though it is more terrestrial than many tropical relatives.
Species
Pacific Tree Frog (Pseudacris regilla), also known as the Pacific Chorus Frog.
Family
Order: Anura; Family: Hylidae; Genus: Pseudacris. Like other Hylids, it possesses adhesive toe pads for climbing, though it is more terrestrial than many tropical relatives.
Size
A small species, adults typically measure 2.5 to 5 cm (1 to 2 inches) in snout-to-vent length. Females are generally slightly larger than males.
Conservation
IUCN Status: Least Concern. Populations are generally stable and widespread, though they face threats from habitat loss and the spread of the chytrid fungus (Bd).
Description
The Pacific Tree Frog is the quintessential chorus frog of the West Coast. Despite its small size, its collective voice can be deafening on spring nights. Its ability to change color from bright green to dull brown within minutes allows it to masterfully blend into varied environments.
Key Features
Dark eye stripe (mask), small adhesive toe pads, and a highly variable dorsal color (often green or brown).
Physical Description
A small, slender frog with a relatively large head, distinctively long toes tipped with small but noticeable expanded toe pads. It features a rounded snout and a noticeable dark mask extending through the eye.
Skin Texture & Coloration
Skin is generally smooth but can appear finely granular. Color is highly variable, ranging from shades of green to tan, brown, or grey. This specific individual shows a tan/light brown dorsal color with darker mottling and a characteristic dark eye stripe.
Distinguishing Features
The most definitive field mark is the dark 'eye mask'—a stripe stretching from the nostril, through the eye, to the shoulder. Another key feature is the presence of small toe pads and an often-visible dark 'Y' or triangle mark on the head.
Habitat
Highly adaptable, found in forests, meadows, pastures, and even urban gardens. They require slow-moving water or seasonal ponds for breeding but spend much of the year in moist terrestrial vegetation.
Geographic Range
Widespread along the Pacific coast of North America, from British Columbia, Canada, south through Washington, Oregon, and California into Baja California, and east into Montana and Nevada.
Behavior
Primarily nocturnal but often active during the day in the breeding season. They are excellent climbers but are frequently found near the ground. They are known for their 'sham' death behavior when threatened.
Diet & Feeding
Opportunistic carnivores; adults eat a variety of small invertebrates including beetles, flies, spiders, and ants using a 'sit-and-wait' ambush strategy and a sticky tongue.
Reproduction
Breeding occurs in early spring/late winter triggered by rain. Males migrate to water and form large choruses. Females lay small clusters of 10-70 eggs attached to submerged vegetation.
Vocalizations
The call is a high-pitched, two-part 'rib-it' or 'kreck-ek.' This specific sound is the 'standard' frog sound produced by Hollywood films because it was common around California film studios.
Life Cycle
Eggs hatch into dark-colored tadpoles within 2-3 weeks; metamorphosis occurs in about 2-3 months depending on water temperature. Adults can live several years in the wild.
Conservation Status
IUCN Status: Least Concern. Populations are generally stable and widespread, though they face threats from habitat loss and the spread of the chytrid fungus (Bd).
Toxicity & Defense
Not toxic to humans. They rely on superb camouflage and high-speed hopping to evade predators. When caught, they may secrete a mild mucus and inflate their bodies to appear larger.
Ecological Role
A vital link in the food chain; they consume vast quantities of insects and serve as a primary food source for snakes, birds, and larger amphibians.
Similar Species
Sierran Tree Frog (P. sierra) and Baja California Tree Frog (P. hypochondriaca) are nearly identical and were formerly considered the same species; they are primarily distinguished by geographic range.
Observation Tips
Listen for loud 'rib-it' choruses near ponds on rainy spring nights. Use a flashlight to spot the reflecting eyes. They are often found hiding in moist spots like under flower pots or in leafy shrubs during the day.
Handling & Safety
Safe to handle, but always wet your hands first as dry skin can damage their permeable skin. Ensure your hands are free of soap, lotion, or insect repellent. Always wash hands after handling to avoid salmonella risk.
Seasonal Activity
Most active during the wet season (winter and spring). In drier or colder parts of their range, they may aestivate or hibernate in underground burrows or under thick leaf litter.
Cultural Significance
A symbol of spring in Western North America. It is a popular subject in classroom biology and serves as a primary 'soundtrack' for night scenes in global cinema.
Interesting Facts
This frog is the official state amphibian of Washington. Its 'rib-it' call is so iconic that it is used in movies set in places where the frog does not even exist, such as tropical jungles or Europe.