Pacific Tree Frog or Pacific Chorus Frog (Pseudacris regilla)
Order Anura, Family Hylidae (Tree Frogs), Genus Pseudacris. This genus is known as the chorus frogs, characterized by their terrestrial or semi-arboreal habits and loud, musical mating choruses.
Species
Pacific Tree Frog or Pacific Chorus Frog (Pseudacris regilla)
Family
Order Anura, Family Hylidae (Tree Frogs), Genus Pseudacris. This genus is known as the chorus frogs, characterized by their terrestrial or semi-arboreal habits and loud, musical mating choruses.
Size
A small frog, with adults typically measuring between 0.75 to 2 inches (1.9–5.1 cm) in Snout-to-Vent Length (SVL). Females are generally slightly larger than males.
Conservation
IUCN Status: Least Concern. Populations are generally stable and widespread, though they face local threats from habitat loss, pollution, and the spread of the chytrid fungus.
Description
The Pacific Tree Frog is a charismatic and resilient amphibian that defines the nighttime soundscape of the American West. Despite its diminutive size, its voice is booming, and its ability to adapt to human-altered landscapes makes it one of the most frequently encountered frogs in its range.
Key Features
Dark eye mask, Y-shaped mark between eyes, small toe pads, and a body color that can shift between green and brown.
Physical Description
A small, slender frog with a relatively large head and prominent eyes with horizontal pupils. The limbs are long and thin, featuring moderately sized toe pads for climbing through vegetation. It has a distinct, visible tympanum (eardrum).
Skin Texture & Coloration
The skin is generally smooth or finely granular. Coloration is highly variable, ranging from shades of green to brown, tan, or gray. This specimen shows a brownish-olive dorsal color with dark, irregular spots or blotches. A characteristic dark 'mask' or stripe usually extends from the nostril through the eye to the shoulder.
Distinguishing Features
The most reliable diagnostic feature is the dark brown or black eye stripe (mask) extending to the shoulder. They also frequently possess a Y-shaped or triangular mark on the top of the head between the eyes, and small but distinct adhesive toe pads.
Habitat
Extremely versatile, found in forests, grasslands, chaparral, and even suburban gardens. They require slow-moving water or seasonal ponds for breeding but spend much of the year in moist terrestrial vegetation or underground in burrows.
Geographic Range
Common across the Pacific coast of North America, from British Columbia, Canada, through Washington, Oregon, and California, extending inland to Montana and Nevada.
Behavior
Primarily nocturnal but often active during the day in the breeding season. They are excellent climbers but are frequently found in low-lying grass and shrubs. They have the ability to change color from light to dark based on temperature and moisture.
Diet & Feeding
Insectivorous, feeding on a wide variety of small invertebrates including beetles, flies, spiders, and ants. They utilize a sit-and-wait ambush strategy, using their sticky tongues to capture prey.
Reproduction
Breeding occurs from winter to early summer depending on elevation and latitude. Males migrate to water and form loud choruses to attract females. Eggs are laid in small, jelly-like clusters attached to underwater vegetation.
Vocalizations
The classic 'ribbit' or 'kree-ek' call, which is famously the sound often used in Hollywood movies for any frog scene, regardless of the film's geographical setting. The call is loud, high-pitched, and two-noted.
Life Cycle
Eggs hatch into tadpoles within 2-3 weeks. The tadpole stage lasts about 2 to 2.5 months before metamorphosis. After developing legs and absorbing their tails, froglets emerge and reach sexual maturity within one year.
Conservation Status
IUCN Status: Least Concern. Populations are generally stable and widespread, though they face local threats from habitat loss, pollution, and the spread of the chytrid fungus.
Toxicity & Defense
Non-toxic to humans. Their primary defense is camouflage, which they enhance by changing their color to match their surroundings. When threatened, they may leap away into dense grass or water.
Ecological Role
They serve as a vital link in the food web, controlling insect populations and serving as a major food source for birds, snakes, and larger mammals. Their health often mirrors the health of local wetlands.
Similar Species
Boreal Chorus Frog (Pseudacris maculata) which has longer dorsal stripes rather than blotches, and the California Tree Frog (Pseudacris cadaverina) which lacks the dark eye mask.
Observation Tips
Look for them in wet grass or near garden ponds on rainy nights. In early spring, follow the sound of their 'ribbit' chorus to find breeding aggregations in shallow water.
Handling & Safety
Safe to handle, but always wash hands before and after. Use wet hands to avoid damaging their permeable skin. Avoid handling if you have recently applied lotion or insect repellent, as these can be fatal to the frog.
Seasonal Activity
Active year-round in milder coastal climates, but they will hibernate (brumate) in colder inland or high-elevation areas during the winter months.
Cultural Significance
As the source of the 'Hollywood Ribbit,' this frog has had a massive global cultural impact. It is also often used as a flagship species for backyard wildlife conservation in the Pacific Northwest.
Interesting Facts
This species is the 'official state amphibian' of Washington. Its call is so iconic that it has been used as background noise in films set all over the world, even in environments where the frog doesn't exist.