Pacific Treefrog (Pseudacris regilla)
Order Anura, Family Hylidae, Genus Pseudacris, Species P. regilla. They are members of the chorus frog group, known for their vocal abilities and small size.
Species
Pacific Treefrog (Pseudacris regilla)
Family
Order Anura, Family Hylidae, Genus Pseudacris, Species P. regilla. They are members of the chorus frog group, known for their vocal abilities and small size.
Size
Adult SVL ranges from 2.5 to 5 cm (1 to 2 inches). Females are generally larger than males. Metamorphs are very tiny, often less than 1.5 cm.
Conservation
IUCN Status: Least Concern. Populations are generally stable and widespread, though they are sensitive to habitat loss, pollution, and the chytrid fungus (Batrachochytrium dendrobatidis).
Description
The quintessential frog of the American West, this tiny master of disguise can change from bright leaf green to bark brown in minutes. They are often found far from water in trees or shrubs until the first rains trigger their massive, deafening migration to breeding ponds.
Key Features
Dark eye mask, small toe pads, 'rib-bit' call, and highly variable green or brown dorsal color.
Physical Description
Small and slender with a rounded snout. It features prominent, slightly large eyes with horizontal pupils. The legs are long and slender with small but distinct toe pads (disks) used for climbing. The tympanum is distinct but smaller than the eye.
Skin Texture & Coloration
Skin is smooth and moist. They are highly variable in color, ranging from shades of green, tan, brown, or grey. A thick, dark 'mask' or stripe runs through the eye from the nostril to the shoulder. The belly is creamy white or pale yellow.
Distinguishing Features
The most diagnostic feature is the dark brown or black eye mask that extends from the snout to the shoulder. They also possess small toe pads and lack the extensive webbing seen in aquatic frogs.
Habitat
Highly adaptable; found in forests, meadows, urban gardens, and grasslands. They require quiet water for breeding, such as ponds, seasonal pools, or slow-moving streams, from sea level to high mountain elevations.
Geographic Range
Common throughout the Pacific coast of North America, from British Columbia through Washington, Oregon, and California into Baja California, and east to Montana and Nevada.
Behavior
Primarily nocturnal or crepuscular, though active during the day in breeding season. They are exceptional climbers and jumpers. They can change color over several minutes to blend in with their environment (metachrosis).
Diet & Feeding
Insectivorous. Adults eat a variety of small invertebrates including flies, beetles, spiders, and ants. They use a sit-and-wait strategy combined with a sticky, projectile tongue.
Reproduction
Breeding occurs from early winter to summer depending on latitude. Males gather at ponds and call to attract females. Amplexus is axillary. Eggs are laid in small gelatinous clusters (10-70 eggs) attached to submerged vegetation.
Vocalizations
The classic Hollywood frog sound: a two-part 'rib-bit' or 'cree-ek'. It is a loud, high-pitched croak. In a chorus, thousands of individuals can be heard from over a mile away.
Life Cycle
Eggs hatch in 1-3 weeks. Tadpoles are dark with high tail fins, taking 2-3 months to metamorphose. Life span is typically 3-5 years in the wild, though many do not survive the first year.
Conservation Status
IUCN Status: Least Concern. Populations are generally stable and widespread, though they are sensitive to habitat loss, pollution, and the chytrid fungus (Batrachochytrium dendrobatidis).
Toxicity & Defense
Not toxic to humans. They rely on cryptic coloration (camouflage) and their ability to leap long distances to avoid predators like snakes, birds, and small mammals.
Ecological Role
High-volume consumer of insects and a critical food source for garter snakes, herons, and predatory fish. They bridge the energy gap between aquatic and terrestrial ecosystems.
Similar Species
Boreal Chorus Frog (Pseudacris maculata) which has three dorsal stripes rather than a mask, and the California Chorus Frog (P. sierra) which is genetically distinct but look nearly identical.
Observation Tips
Look near water sources on rainy nights during spring. Use a flashlight to spot eye-shine on low vegetation or listen for the unmistakable loud 'rib-bit' chorus.
Handling & Safety
Safe to handle but not recommended. Amphibian skin is porous; oils/chemicals from human hands can harm them. If handling is necessary, ensure hands are wet and free of soap or lotion.
Seasonal Activity
Active year-round in milder coastal areas; in colder regions, they brumate (hibernate) under logs or in leaf litter during winter to emerge for early spring breeding.
Cultural Significance
Commonly depicted in children's books and media; serves as an important indicator of wetland health in the Pacific Northwest.
Interesting Facts
The 'rib-bit' call of the Pacific Treefrog is the standard frog sound used in Hollywood movies, regardless of where the movie is actually set, because the frog is so common near Los Angeles.