Rocky Mountain Tailed Frog

Taxon, Status, and Ranks Habitat Photos
General Description State Status Comments
Identification Tips Inventory & Research Needs Key Features
Phenology Threats & Mgmt Concerns
Range References Distribution Map

Taxon, Status, and Rank

Species Ascaphus montanus     Mittleman & Myers, 1949
Family Ascaphidae or Leiopelmatidae
(Tailed Frogs)
Status State Candidate Species, Federal Species of Concern
State Rank S2?
Global Rank G4

General Description

This is a moderately small (37-50 mm snout-vent length), slender-bodied frog with rough skin. The head is relatively large, flattened and slightly broader than it is long. The snout tapers anterior to the eyes and is relatively short. The pupil is vertical. An eyestripe extends from the snout to the shoulder. The toes are slightly webbed and the outer two hind toes are flattened. The dorsal color is usually similar to the substrate of the habitat occupied. The males have a tail-like copulatory organ, tubercles on the palm and forearm and, during the breeding season, small dark pads on the sides of the abdomen.

The tadpole has a somewhat flattened body with dorsal eyes, a ventral suctorial oral disc (mouth) and a low fin that originates at the dorsal tail-body junction. The oral disc covers about 1/3 to _ of the lower body surface. The tip of the tail is broadly rounded and typically has a white spot bordered by black. The spiracle is located on mid-belly (midventral) and the nostrils are located closer to the eyes than the snout.

The eggs are unpigmented, deposited in strings of 40-80 eggs and attached to the undersides of rocks in cool flowing steams.

No vocalizations have been documented. Moreover, Rocky Mountain Tailed Frogs lack some of the structures used to make sounds (tongue and vocal sacs) found in other frogs.

See Photos Page.

Identification Tips

The tail appendage of the male is unique among anurans. Rocky Mountain Tailed Frogs look similar to Pacific Treefrogs, but treefrogs have horizontal pupils, circular discs (“toe-pads”) at the tips of their fingers and toes, rounded (rather than flattened) 4th and 5th toes on their hind feet, and typically lighter, brighter ground coloration (often light browns and greens). Great Basin Spadefoots have vertical pupils (the only other Washington anuran that does) but they are typically found only in arid habitats and have black spades on the under side of their rear feet. Tailed frogs (both Coastal and Rocky Mountain taxa) have the only tadpoles in Washington able to adhere to rocks in fast-flowing streams with a large sucker-like mouth. See Key Features Page.


Present year-round in and near perennial streams. Primarily night active, but tadpoles and frogs can also be observed during the day. Frogs are most active from April to October, but this varies by site and conditions. Mating takes place in the fall. Females are thought to store sperm until eggs are deposited in the summer. Eggs hatch in approximately six weeks. In Washington populations of the Rocky Mountain Tailed Frog, the larval phase appears to last three years. Metamorphosis usually takes place in late summer.


In Washington, populations are found only in the Blue Mountains. See Distribution Map.

For information on the complete range of this species, see NatureServe Explorer.

Habitat and Habits

They are restricted to perennial streams found in or associated with cold, clear, rocky streams in mature forests. All life stages are adapted for life in fast-flowing streams. The male’s “tail” is used for internal fertilization, which prevents sperm from being washed away. Eggs are attached to the undersides of rocks to keep them in place. The tadpoles have a large ventral suctorial mouth that allows them to feed and move in high-energy streams without loosing contact and unintentionally drifting.

State Status Comments

The Rocky Mountain Tailed Frog (Ascaphus montanus) was split from the Coastal Tailed Frog (Ascaphus truei) based on genetic differences. Lack of recent survey information has prevented an unambiguous determination of the Natural Heritage state rank. Based on its small range in Washington, the state rank of the species will most likely be S2 unless the species proves to be common or abundant where it occurs.

Inventory and Research Needs

Inventory is needed in the Blue Mountains. The Washington Department of Fish and Wildlife Herp database contains only 9 locations for this species, only two of which are reports from the last 20 years. The following are drainages where Rocky Mountain Tailed Frogs have been found in Washington with the most recent observation year in parentheses: George Creek, Asotin County (1958); Wenatchee Creek, Garfield County (1959); and each of the North (2001) and Wolf (1997) Forks of the Touchet River, Columbia County.

Research is needed on the long-term consequences of land management practices (forestry practices, livestock grazing) on the Washington populations of the Rocky Mountain Tailed Frog.

Threats and Management Concerns

This species is vulnerable to management practices that alter the riparian or aquatic zones of streams, especially those that change the moisture regime, increase stream temperature, increase sediment load, reduce woody debris input and change stream bank integrity. Protection of headwater streams is particularly important for this species.

The Rocky Mountain Tailed Frog is one of the seven Forests and Fish Agreement (FFR) target species, but less concern for this species has been voiced in the FFR community because much of the known range lies on federal lands, and relatively little of the known range is under FFR jurisdiction. However, some of the area of the known range also represent livestock rangeland, and livestock impacts, elsewhere well known to influence riparian systems, are currently not being paid attention to as potentially of significance to this species.


Bull and Carter (1996), Corn and Bury (1989), McDiarmid and Altig (1999), Nielson et al. (2001), Nussbaum et al. (1983), Stebbins (1985), Welsh (1990), Zug et al. (2001).


Personal communications: M. Hayes

Hallock, L.A. and McAllister, K.R. 2005. Rocky Mountain Tailed Frog. Washington Herp Atlas.

Last updated: February 2005

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