The American pika (Ochotona princeps) is a small, herbivorous mammal of the family Ochotonidae, closely related to rabbits and hares (order Lagomorpha). It is native to the mountainous regions of western North America, typically inhabiting rocky slopes and talus fields at or above the tree line higher elevation. Unlike most mammals of similar size, the American pika is diurnal, being active primarily during the day. It employs two distinct foraging strategies: directly consuming vegetation or gathering and storing plant materials in "haypiles" to sustain itself through the winter months, a behavior known as haying.
Pikas are vocal animals, using a variety of calls and songs both to warn of approaching predators and during the breeding season. Predators of the American pika include eagles, hawks, coyotes, bobcats, foxes, and weasels.
Recent studies suggest that populations in the southwestern United States are declining due to habitat loss and global warming. Despite these regional declines, the American pika is overall assessed as a species of Least Concern by the IUCN and remains common in the northwestern United States and Canada. Taxonomy
The American pika was first described scientifically by the Scottish naturalist John Richardson in 1828, in his comprehensive work Fauna Boreali-Americana, which cataloged the animal species of northern North America. Richardson initially classified the species within the genus Lepus, primarily containing hares and rabbits, under the name Lepus (Lagomys) princeps. The use of the subgenus Lagomys reflected an early attempt to distinguish these small mammals from true rabbits and hares, though this classification predated the formal recognition of pikas as a separate genus.
Subsequent taxonomic revisions placed the American pika in the genus Ochotona, which is now recognized as the sole genus comprising all pikas. This genus is distinct within the family Ochotonidae, which itself is part of the order Lagomorpha, alongside rabbits and hares. The genus name Ochotona is derived from the Mongolian word for pika, reflecting the species' native range across North America and parts of Asia.
Over time, several subspecies of the American pika have been identified, primarily based on geographic distribution and minor morphological differences. However, taxonomic opinions on these subspecies vary, and ongoing genetic studies continue to refine the understanding of intraspecific variation within Ochotona princeps.
Description
American pikas, historically known as "little chief hares", is a small, rounded mammal with a compact, ovate body adapted for life in cold alpine environments. Adults typically measure in length, with hind feet ranging from . They usually weigh between 121 and 176 g (4.3–6.2 oz), though body size varies among populations and regions. In some areas, males are slightly larger than females. In populations exhibiting sexual dimorphism, males tend to be slightly larger than females.
The American pika is intermediate in size among pika species. Its notable features are suborbicular ears, densely furred feet with black pads at the toes, and a dense undercoat that provides insulation during winter months. The species is well adapted to high-elevation habitats. Its dense fur provides insulation against cold temperatures, covering the entire body, including the soles of the feet, except for small black pads at the toes. Its hind legs are only slightly longer than its forelegs, giving the animal a low and even stance typical of pikas, and its hind feet are relatively short compared to most other lagomorphs. The soles of the feet are densely furred, except for black pads at the ends of the toes. The ears are moderately large, rounded, and hairy on both surfaces, typically dark with white margins. The species has a relatively longer "buried" tail compared to most other lagomorphs, meaning that the tail is so short and densely covered with fur that it appears hidden within the animal's body fur rather than projecting outward. This adaptation is thought to provide extra insulation and protection from cold alpine winds.
The skull of the American pika is slightly rounded, with a broad and flat preorbital region that distinguishes it from related species. The cranium is relatively compact and adapted to support a strong bite force, useful for cutting and processing fibrous alpine vegetation. The zygomatic arches are well developed to anchor large masseter muscles. The maxillae contain a single large fenestration rather than the numerous small openings typical of rabbits and hares, a structural difference that lightens the skull while maintaining strength for chewing coarse plant material.
Fur coloration is the same in both sexes but varies by subspecies and season. The dorsal fur ranges from grayish to cinnamon-brown, often with tawny or ochraceous tones in summer. In winter, the fur becomes grayer and longer, while the dense underfur is slate-gray or lead-colored, and the ventral fur is whitish. Males are referred to as "bucks" and females as "does," as with rabbits.
Distribution and habitat
The American pika is found throughout the mountainous regions of western North America, ranging from central British Columbia and Alberta in Canada to the U.S. states of Oregon, Washington, Idaho, Montana, Wyoming, Colorado, Utah, Nevada, California, and New Mexico. Of the approximately 30 existing species of pika, it is one of only two native to North America, the other being the collared pika (O. collaris). The collared pika occurs farther north, and its distribution is separated from that of the American pika by a gap of about across British Columbia and Alberta.
American pikas primarily inhabit scree and talus fields, often surrounded by alpine vegetation, and are also found in piles of broken rock. They occasionally occupy man-made substrates such as mine tailings or piles of scrap lumber. Pikas typically establish dens and nests below rock surfaces, usually within spaces in diameter, but they often perch on larger, more prominent rocks. They are commonly found near or above the tree line in cool, moist microhabitats such as high peaks or along watercourses.
The species is highly sensitive to heat stress and is intolerant of high diurnal temperatures. In the northern parts of their distribution, the species occurs from near sea level up to around 3,000 m (9,800 ft), In the northern parts of its range, the American pika can occur near sea level. While in southern regions such as California and New Mexico, it is rarely found below . Although pikas do not dig extensive burrows, they may enlarge existing crevices in the talus to create shelter.
Diet The American pika is a generalist herbivore, consuming a wide range of green vegetation, including various grasses, sedges, thistles, and fireweed. Although pikas can meet their water requirements through moisture in plants, they will drink water when it is available.Martin, J. W. (1982). "Southern pika (Ochotona princeps) biology and ecology: a literature review."
American pikas use two foraging strategies: direct consumption of food (feeding) and caching vegetation in "haypiles" for winter use (haying). They feed throughout the year, but haying is confined to summer months. Because they do not hibernate, pikas have higher energy requirements compared to many other montane mammals. During peak haying periods, an individual can make about 13 trips per hour to collect vegetation—over 100 trips per day. The timing of haying is influenced by weather patterns, particularly the amount of snow and timing of snowmelt from the previous winter. At lower elevations, haying often begins before snow has melted at higher elevations, whereas at higher elevations it continues after activity has ended in lower areas.
When haying, pikas harvest plants in a deliberate sequence corresponding to seasonal plant growth (phenology). They actively select plants with higher caloric, protein, lipid, and water content. Forbs and tall grasses are more likely to be harvested for haying than eaten immediately. Haypiles are typically stored under talus near the talus–meadow interface, though they may also be built on the talus surface. Males usually store more vegetation than females, and adults store more than juveniles.
Like all members of Lagomorpha (rabbits, hares, and pikas), the American pika practices coprophagy, producing and consuming cecotropes to extract additional nutrients from its food. Cecotropes provide more energy than stored plant material and may be eaten directly or stored for later consumption.
Reproduction Adult males and females with adjacent territories form mated pairs. When multiple males are present, females exhibit mate choice. The species is a reflex ovulator—ovulation occurs only after copulation—and is also seasonally polyestrous. Females typically produce two litters per year, with each litter averaging three young. Breeding begins roughly one month before snowmelt, and gestation lasts around 30 days. Parturition occurs as early as March at lower elevations and between April and June at higher elevations. Lactation greatly depletes fat reserves, and a female will only raise a second litter if the first fails to survive, despite undergoing postpartum estrus.
Pikas are born altricial, being blind, lightly furred, and with fully erupted teeth. Newborns weigh between . Their eyes open at around nine days of age. Mothers spend most of the day foraging and return to the nest roughly every two hours to nurse their young. Juveniles become independent after about four weeks, coinciding with weaning. Young pikas may remain within their natal range or move to adjoining territories, generally avoiding areas occupied by relatives. Dispersal is primarily driven by competition for territories.
Life history
The American pika is diurnal. The total area used by an individual pika is called its home range, approximately 55% of which is defended as territory against intruders. Territory size varies between , depending on rock formation, distance to vegetation, and vegetation quality. Home ranges may overlap, with territories of mated pairs being closer together than those of same-sex neighbors. The spatial distance between members of a pair is greatest in early and midsummer and decreases in late summer and autumn. Territorial defense often involves aggressive displays, though direct confrontations are rare and typically occur between same-sex adults that are unfamiliar with one another. Intrusions onto another pika's territory usually happen when the resident is inactive. Territorial behavior increases during the haying season.
American pikas are highly vocal, using both calls and songs for communication. Short calls warn of nearby predators, while longer songs are associated with the breeding season (males only) and with territorial behavior in autumn (both sexes). Predators of the pika include eagles, hawks, coyotes, bobcats, cougars, foxes, and weasels.
Conservation and decline