Pikas are small, rodent-like mammals found exclusively in the mountains of Asia and North America. They comprise the family Ochotonidae, one of the two extant families of lagomorphs, the other being Leporidae (rabbits and hares). These animals are characterized by an ovate (egg-shaped) body covered evenly by fur and have short limbs and rounded ears. Often found hiding under the burrows, they typically feed on grasses, weeds, shrubs, wildflowers, mosses, and lichens.
Currently, 34 species of pikas are grouped under Ochotona, the only extant genus of the family. Though most of these species are found in Asia, two species (American and collared pika) are exclusive to North America.
They vary between 5.9 to 9.1 in (15 to 23 cm) in body length and weigh around 4.2 to 12.3 oz (120 and 350 gm).
They are the smallest members in the lagomorph group, with ovate, stocky bodies, short limbs, and large, rounded ears that are evenly coated with fur. The fur is typically grayish-brown, though some species, like the Chinese red pika, have a rusty red coat. However, they lack an external tail.
Like other lagomorphs, pikas have fur at the bottom of their paws but lack paw pads.
These mammals possess gnawing incisors and have fewer molars than rabbits. They also lack canines like other lagomorphs.
Their dental formula is 2.0.3.2/1.0.2.3 = 26.
The name pika is derived from the Tungusic word pika, while the order Ochotonidae originates from the Mongolian word ogotno.
Currently, 34 species of pikas are grouped under a single genus, Ochotona. This genus is further divided into four subgenera: Conothoa (Mountain pikas), Ochotona (Shrub-steppe pikas), Pika (Northern pikas), and Alienauroa.
Originally, pikas had a much wider distribution, which included Western Europe and Eastern North America, where they are no longer found today. For instance, fossils of the steppe pika dating back to the Pleistocene Epoch have been unearthed from parts of Europe, including the United Kingdom, Italy, and Poland. A few genera of pikas that went extinct include Ochotonoides, Ochotonoma, Oklahomalagus, Albertona, Alloptox, Oreolagus, and Paludotona, among others.
They first appeared in Asia between the late Eocene and the early Oligocene Epochs and diversified with the parallel increase in the distribution of C3 grasses during the late Oligocene to middle Miocene Epoch. It was around this time that they reached the peak of their diversity.
However, most pikas went extinct at the cusp of the Pliocene Epoch as C4 plants gradually replaced the C3 grasses. This transition in vegetation was caused by the rapid cooling of the atmosphere in the late Miocene, which led to the gradual rise of leporids.
These mammals are restricted to the mountainous regions of Asia and North America. The northern pika has the broadest global distribution, ranging from the Ural Mountains to the eastern coast of Russia and Hokkaido Island of Japan.
While most species are found in Asia, with 23 just in China itself, only two species are spotted in North America: the American and the collared pika. While the American pika lives in the mountainous regions of the western United States and southwestern Canada, the latter is found in British Columbia, the Yukon, Alaska, and the Northwest Territories.
Pikas reside either in piles of broken rock debris (talus) or in meadows where they live in burrows. About half of the Asian species and both the North American species are rock-dwelling and do not form burrows. The Pallas’s pikas and Afghan pikas are found in both types of ecological niches.
The collared pika has been observed living on nunataks, isolated peaks surrounded by glaciers, while the large-eared pika in the Himalayas has been found at elevations as high as 20,000 ft (6,000 m). In mountainous regions, particularly in Eurasia, pikas often share their burrows with birds like snowfinches, which nest in the same spaces.
Pikas are generalist herbivores that feed on plant matter. They typically consume grasses, sedges, forbs, shrub twigs, weeds, tall wildflowers, thistles, mosses, and lichens.
Collared pikas, however, have been found consuming dead birds and animal feces during winters.
Unlike rabbits and hares, pikas are mostly diurnal (active during the day), while some are crepuscular (active during twilight hours). The only nocturnal species is the steppe pika (Ochonta pusilla).
They do not hibernate in winter; instead, they navigate in tunnels under rocks and snow. Sometimes, on clear days, they are found sunning themselves on large rocks.
Pikas either eat their food immediately or store it for future use. For instance, after their breeding season in the summer, they create caches of vegetation called haypiles. By late June, they begin traveling to meadows to gather twigs, stems, and other plant materials, which they carry back to their territories in their mouths. They then stack these materials (a behavior known as haymaking) in crevices, under overhanging rocks, or along the edges of boulders. Males start the haymaking process, followed by females and juveniles. Occasionally, pikas steal vegetation from nearby haypiles belonging to other groups, a behavior known as kleptoparasitism.
Although they generally prefer foraging in temperatures below 77 °F (25 °C), the foraging patterns vary seasonally, depending on the type of plants available and their calorie, lipid, water, and protein content.
After food is ingested, they process it in their gastrointestinal tract and expel unwanted food matter as feces. However, if the food is fibrous and hard to digest, they ferment the fiber in the cecum and produce cecotropes, which are nutrient-rich droppings ingested by these mammals (caecotrophy). Nutrients from these cecotropes are then easily absorbed in the small intestine.
Most pikas live in family groups and mutually share the duties of foraging and defending a mutual territory. However, the North American pikas are generally solitary, except in the breeding season.
Burrowing pikas are extremely social and live in family groups defending a mutual territory. They are generally amiable, with members of all ages and sexes sitting next to each other, grooming (allogrooming) and rubbing their noses. They get aggressive and engage in long chases only if an individual from another family group invades their territory. In contrast, rock-dwelling pikas are relatively less social, and their territories are widely spaced and scent-marked. They usually encounter their neighbors only once or twice a day.
These mammals have distinct calls for species recognition, predator warning, territorial defense, and attracting potential mates. These calls may be short and quick or more drawn-out, resembling the bleat of lamb, but are more high-pitched. When a predator is around, pikas emit a characteristically high-pitched alarm call to their conspecifics; hence, they are also called whistling hares.
These calls vary seasonally. For instance, pikas vocalize more frequently during spring, whereas in summer, these calls become short.
Pikas have an average lifespan of about seven years in the wild. Rock-dwelling pikas generally live longer than burrowing varieties, which barely survive more than one year.
Around late May or early June, when it is the breeding season for pikas, the males vocalize to attract the females for mating. Having mated, the females undergo a gestation period of about 25 to 30 days, following which they give birth to hairless, altricial young with closed eyes and ears.
Generally, rock-dwelling pikas have small litters containing less than five young (usually two), while burrowing species produce multiple large litters each year, with some species, like the steppe pika, carrying as many as 13 young. This species also breeds up to five times per year.
These young are raised alone by the mother, and after a month, they leave to establish their own dens. It takes them a few more months to mature completely.
Of the two litters the rock-dwellers typically give birth to, only one is successfully weaned.
They are usually preyed upon by stoats, martens, weasels, coyotes, and birds of prey, including hawks, eagles, and owls.
Currently, four species of Asian pikas are considered Endangered (EN) according to the IUCN Red List: Ili pika, Kozlov’s pika, Hoffman’s pika, and silver pika. The Sardinian pika (Prolagus sardus) has gone extinct. Such decline in the population of pikas is due to anthropogenic causes, like habitat loss, and environmental factors, such as climate change.
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