American Pika

American Pika

The American pika (Ochotona princeps) is a well-known diurnal species of pika.

They are regarded as herbivorous, smaller relatives of hares and rabbits, and can be found in the mountains of western North America.

Scientific classification

KingdomAnimalia
PhylumChordata
ClassMammalia
OrderLagomorpha
FamilyOchotonidae
GenusOchotona
Scientific NameOchotona princeps

Subspecies

  • O. princeps princeps
  • O. princeps fenisex
  • O. princeps saxatilis
  • O. princeps schisticeps
  • O. princeps uinta

Characteristics

American pikas, known as little Chief hares in the 19th century, have a small, round ovate body. Their body lengths are between 6.4 and 8.5 in (162 and 216 mm).

Their hind feet range from 25 – 35 mm (1 – 1½  in). Generally, they weigh around 6.0 oz (170 g). Body size may differ between populations. Males are fairly larger than females in populations with sexual dimorphism.

Among pikas, the American pika is said to be intermediate (medium) in size. The pika’s hind legs do not appear to be much longer than its front legs. Except for black pads at the ends of the toes, it has heavily furred soles on its feet.

The ears are averagely wide and suborbicular and are hairy on both surfaces, generally dark with white margins. Compared to other lagomorphs, the “buried” tail of the pika is longer relative to body size.

The American pika has a slightly rounded skull with a preorbital region. For both sexes of the pika, the fur colour is the same, although it varies by subspecies and season.

During the summer, the pika’s dorsal fur ranges from cinnamon-brown to greyish, sometimes coloured with ochraceous or tawny hues.

The fur gets greyer and longer throughout winter. The thick underfur is usually lead-coloured or slate-grey. Males are known as bucks, while females are known as does (like rabbits).

Behaviour

The American Pika is said to be diurnal. Approximately 55% of its home range is territory that is defended against intruders.

The size of the territory may vary from 410 to 709 m² and depends on the configuration, vegetation quality, and vegetation distance.

The home ranges of pikas can overlap, with the distances of a mating pair’s home ranges being shorter than those of the nearest neighbours of the same sex.

During early and mid-summer, spatial distances between adults of a pair are greater and decrease during late summer.

Pikas are very aggressive when defending their territories. Aggressive interactions are uncommon and usually occur between members of the same sex and other individuals unfamiliar with each other.

A pika may intrude on the territory of another, but generally when the resident is not closeby or active. Territorial behaviour increases during haying.

Females show mate preference when more than one male is available. Pikas are known as reflex ovulators (ovulation only occurs after mating) and are seasonally polyestrous.

A female produces two litters each year, and each of these litters consists of three young averagely. Mating takes place one month before the snow melts and the gestation period takes about 30 days.

Parturition occurs at lower elevations as early as March but occurs at higher elevations from April to June.

Pikas are born slightly altricial, slightly haired, being blind, and have fully erupted teeth. At birth, they weigh between 10 and 12 g. They are able to open their eyes at about nine days old.

During most of the day, mothers forage and come back to the nest once every two hours to feed and groom the young. After four weeks, young become independent, and at the same time, they are weaned.

Young may stay in an adjoining or their natal home range. While in their home range, the young tend to occupy areas away from their families and relatives as far as possible.

Pikas are vocal, making use of both songs and calls to communicate with each other. When a predator is close by, a call is used to warn, and a song is used during the breeding season (only males) and during fall (both males and females).

Predators of the pika include hawks, eagles, coyotes, bobcats, weasels, and foxes.

Diet

The American Pika is a herbivorous generalist. It consumes a wide range of green plants, including various sedges, grasses,  thistles, and fireweed.

While a pika can satisfy its water demand from the vegetation consumed, if it is available in its area, it drinks water.

Pikas have two distinct foraging methods; they eat food directly (feeding), or they store food in hay piles to be used in the winter (haying) for a food source.

Pikas have higher energy needs than other montane mammals because they do not hibernate.

They also make 13 trips per hour which make up to over 100 trips a day to gather vegetation while haying. The timing of haying tends to correspond to the amount of precipitation from the previous winter.

Haying starts in areas at lower elevations until the snow at high altitudes melts; haying continues at higher elevations after it stops at lower elevations.

In a deliberate sequence, while haying, pikas harvest plants corresponding to their seasonal phenology. They seem to determine the nutritional value of available harvest and food accordingly.

Pikas prefer plants with the highest nutritional; carbohydrate, lipid, and water content. Haypiles are stored under the talus near the talus-meadow interface, although they may be built on the surface of the talus.

Males usually store more vegetation than females, and adults generally store more than juveniles. Two types of faecal droppings are deposited by pikas: Soft, black, shiny pellets (these pellets are formed in the caecum) and hard, brown, round pellets.

Habitat and distribution

The American pika can be found on the mountains of western North America, Alberta in Canada to the US states of Oregon, central British Columbia, Washington, Montana, Idaho, Colorado, Wyoming, Utah, California, Nevada, and New Mexico.

Pikas occupy talus fields in alpine areas that are bordered by suitable vegetation.

They may also be found in broken rock piles. Generally, pikas have their den and nest sites between 0.2 to 1 m in diameter under a rock, but also sit on larger and more prominent rocks.

They usually live in the scree next to or above the tree line. Pikas on high peaks or watercourses are restricted to cool, moist microhabitats.

Intolerant of high diurnal temperatures, they can be found near sea level in the northern portion of their range, but they are rarely below 8,200 ft (2,500 m) in the south.

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