The American pika (Ochotona princeps), a diurnal species of pika, is found in the mountains of western North America, usually in boulder fields at or above the tree line. They are herbivorous, smaller relatives of rabbits and hares.[6] Pikas have two different ways of foraging; they either directly consume food or they cache food in piles for the winter (haying).

Pikas are vocal, using both calls and songs to warn when predators are nearby and during the breeding season. Predators of the pika include eagles, hawks, coyotes, bobcats, foxes, and weasels.

Recent studies suggest some populations are declining due to habitat loss and global warming. They generally cannot tolerate temperatures above 25.5 °C (77.9 °F). Currently the American pika is considered a species of least concern.

American pikas, known in the 19th century as "little Chief hares", have a small, round, ovate body. Their body lengths range from 162 to 216 mm (6.4 to 8.5 in). Their hind feet range from 25 to 35 mm (1–1½ in). They usually weigh about 170 g (6.0 oz). Body size can vary among populations. In populations with sexual dimorphism, males are slightly larger than females.

The American pika is intermediate in size among pikas. The hind legs of the pika do not seem to be much longer than its front legs and its hind feet are relatively short when compared to most other lagomorphs. It has densely furred soles on its feet except for black pads at the ends of the toes. The ears are moderately large and suborbicular, and are hairy on both surfaces, normally dark with white margins. The pika's "buried" tail is longer relative to body size compared to other lagomorphs. It has a slightly rounded skull with a broad and flat preorbital region. The fur color of the pika is the same for both sexes, but varies by subspecies and season. The dorsal fur of the pika ranges from grayish to cinnamon-brown, often colored with tawny or ochraceous hues, during the summer. During winter, the fur becomes grayer and longer. The dense underfur is usually slate gray- or lead-colored. It also has whitish ventral fur. Males are called bucks and females are called does like rabbits.

This individual was at 603 m (1,978 ft) above sea level in Mount Baker-Snoqualmie National Forest.

The American pika can be found throughout the mountains of western North America, from central British Columbia and Alberta in Canada to the US states of Oregon, Washington, Idaho, Montana, Wyoming, Colorado, Utah, Nevada, California, and New Mexico. Of the 30 existing species of pika, it is one of only two which inhabit North America, along with the collared pika (O. collaris). In relation to the distribution of the American pika, the collared pika is located farther north of those regions and is separated by a gap of about 500 miles (800 km) extending across British Columbia and Alberta.

Pikas inhabit talus fields that are fringed by suitable vegetation on alpine areas. They also live in piles of broken rock. Sometimes, they live in man-made substrate such as mine tailings and piles of scrap lumber. Pikas usually have their den and nest sites below rock around 0.2–1 m in diameter, but often sit on larger and more prominent rocks. They generally reside in scree near or above the tree line. Pikas are restricted to cool, moist microhabitats on high peaks or watercourses. Intolerant of high diurnal temperatures, in the northern portion of their range, they may be found near sea level, but in the south they are rare below 2,500 m (8,200 ft). Pikas rely on existing spaces in the talus for homes and do not dig burrows. However, they can enlarge their homes by digging.

American Pika (Ochotona princeps saxatilis) Rocky Mountains National Park & Mount Evans Recreation Area

Royle's pika (Ochotona roylei), also called the Himalayan mouse hare or hui shutu, is a species of pika. It is found in Bhutan, China, India, Nepal, and Pakistan.

The most common pika species in the Himalayas, it has a length of 17-22 centimeters. Royle's pika has a slightly arched head, with a rufous-grey body and chestnut-colored head, as well as sparse hair in front of its ears.

This is the most common pika species in the Himalayas, and can be confused with the sympatric large-eared pika. These species are mostly seen in the open rocky mountain edges or slopes, or on ground covered with conifer trees, such as pine, deodar and rhododendron forests. Royle's pika are a crepuscular foraging species, as they tend to be inactive during midday hours. Reduction of activity during the midday is also contributed to increasing temperatures, which causes heat stress on the species. During monsoon season, foraging is encouraged due to greater food availability. The species has also been found near human habitation. It does not make its own nest; rather, it takes narrow creeks and existing burrow systems as its nest, filling it with hay piles and pine leaves. It also uses the rocky areas on the mountains to take refuge and escape from predators.

Though their conservation status according to IUCN Red List is "Least Concern", habitat loss and human habitation in hilly areas are the indirect cause of conservation threats towards them.

Royle’s Pika (Ochotona roylei) - Hemis National Park Ladakh India

The large-eared pika (Ochotona macrotis) is a species of small mammal in the family Ochotonidae. It is found in mountainous regions of Afghanistan, Tibet, Bhutan, India, Kazakhstan, Kyrgyzstan, Nepal, Pakistan and Tajikistan where it nests among boulders and scree.

The large-eared pika has brownish-grey fur tinged with ochre. The forehead, cheeks and shoulder region have a reddish tinge which is more obvious in summer. The underparts are greyish-white. The four legs are all about the same length and the feet, including the soles, are covered with fur. An adult large-eared pika is 15 to 20.4 cm (6 to 8 in) long.

The large-eared pika is native to mountainous regions of Central Asia. Its range includes Afghanistan, Bhutan, India, Pakistan, Nepal, Kazakhstan, Kyrgyzstan and Tajikistan and the provinces of Gansu, Qinghai, Sichuan, Tibet, Xinjiang and Yunnan in China. Its minimum altitude is about 2,300 metres (7,500 ft) and it has been recorded at altitudes of 6,130 metres (20,113 feet) in the Himalayas. The large-eared pika does not make a burrow but lives in crevices among the shattered rock and scree found in mountainous regions.

Large-eared Pika (Ochotona macrotis) - Hemis National Park India

The plateau pika (Ochotona curzoniae), also known as the black-lipped pika, is a species of mammal in the pika family, Ochotonidae.

It is a small diurnal and non-hibernating mammal weighing about 140 g when fully grown. The animals are reddish tan on the top-side with more of a whitish yellow on their under-belly.

They prefer to live in elevations of 3,100 to 5,000 m, mostly in the Tibetan Plateau, which is where the common name originates from. The species is found in China, Pakistan,[citation needed] India, and Nepal in high alpine deserts, steppe and meadows, as well as tropical and subtropical montane forests.

Plateau pikas are considered to be a keystone species as they play a role in recycling nutrients in soil, providing food to predators such as; foxes, weasels, falcons, Asia pole cat, upland buzzard, and owls. They also provide microhabitats by increasing plant richness and their burrows provides nests for small birds and reptiles.

According to the Chinese biologists who have studied the wildlife of the Hoh Xil (northern part of the Tibetan Plateau), plateau pikas are the favorite food of the area's brown bears. In addition to its role as a prey base, the plateau pika is important for soil health in meadows; the burrowing of the species helps to aerate the soil. The species is currently considered threatened, mostly due to aggressive poisoning campaigns by Chinese populations, predominantly to eliminate competition for food with livestock.

Plateau pikas have mating systems such as monogamous and polygynandrous groups, which contain about three males and 3 to 4 females per family along with their offspring. Females can produce 2 to 5 litters of about 2 to 7 offspring with a three-week interval in between each litter which is why this group of lagomorphs are known to have the fastest growth rates of their order. Their breeding season lasts from April to August and the young do not disperse in the year of birth. Males form hierarchies and females are usually philopatric forming reproductive alliances, helping each other in the care of their offspring, males also contribute in parental care when deterring a predator by emitting an alarm call. Pikas are social animals that live in families of two to five adults and their offspring. Males and females both contribute in protecting their family groups from intruders displaying aggressive behaviors towards others who are not part of their family.

Since plateau pikas live in such extremely cold environments and are a non-hibernating species, they have acquired physiological adaptations to better assist with their survival. These adaptations include their high resting metabolic rate and non- shivering thermogenesis along with the production of leptin which is a thermogenesis regulatory hormone.

Unlike hibernating mammals, plateau pikas do not merely rely on excess body fat to combat extremely cold climates. One important physiological adaptation is their ability to alter the type of their adipose tissue, from white to brown, which promotes non-shivering thermogenesis.

Plateau Pika (Ochotona curzoniae) - Tibetan Plateau, Qinghai China