Pika (Ochotona princeps, o. collaris, o. curzonaie)

This page was created by Andre Marques for an undergraduate Animal Behavior course at Davidson College.

Please contact Dr. Case via email if you have and questions or comments: vecase@davidson.edu

* adult pika with typical meadow grasses

Habitat and General Description

    Pikas, along with rabbits, belong to the order Lagomorpha. There are 18 different species of pika, 16 of which make their home in Asia, and 2 of which live in the Rocky Mountains in the western United States (Smith, 1986). All species that have been studied are diurnal, herbivorous, and sexually monomorphic. They are also distinct from other lagomorphs in that they are extremely vocal, and use calls as a principle form of communicationl. There are two main types of pika, those that inhabit arctic steppes (only in Asia), and those that live in rock piles and talus slopes (both Asia and U.S.).

    The arctic-dwelling  (or steppe-dwelling) pika lives at an altitude ranging from 3,000-3,500 meters, at population densities of between 100-300 animals/ha (Smith 1986). During the summer months (Apr.-July) they graze on the plentiful grasses that the meadows provide. As the summer months wind down they begin building "haypile" (Dearing, 1997) caches from which they feed during the long winters. They live in family occupied burrows, usually containing one breeding pair (but sometimes more, see Mating System, below), and between 1 and 3 litters of juveniles at varying stages of development. Average life span does not exceed 2 years.

   The talus-dwelling pika is very different from its Asian cousin. They are far less social, and live in much lower population densities (8-15 animals/ha)  (Smith, 1986). They also tend to live at altitudes that don't exceed 3,000 meters. For food they graze on the lush meadows that invariably border their talus slopes. And as in Asia, they also stockpile food in order to survive the winters. The basic unit in these pikas is the individual. Family bonds are unimportant, and adult burrow life is solitary with the exception of a brief time during mating season (more below). Average life span is uncertain, but it is most likely similar to that of the steppe-dwelling type.

Social Spacing

   The steppe-dwelling pikas live in family occupied home-ranges that center around a main burrow system. This system contains many entrances and exits to the surface in order to escape the intense predation pressure. Their predators range from birds of prey, like the upland buzzard (Buteo hemilasius) and the black kite (Milvus migrans), to mammals like the Asian polecat (Mustela eversmanni) and the marmot (marmota himalayana) (Smith, 1986). The food source around the burrow is abundant during the summer months, and is snow covered during the winter. But by stockpiling their food for the summer they assure themselves a reliable food source year round.

WHY??

   The  most important thing to a family of steppe-dwelling pikas is the burrow system. It is the focus of the home-range. Food is not much of an issue, evident by the fact that males tend not to mind it if individuals from adjacent home-ranges casually graze on their meadow. So the reason pikas don't live in a territory is because the food around them is plentiful enough that they need not waste energy trying to defend it. The key to their survival is to avoid predation, which means having a burrow that is accessible at all times.

   The talus-dwelling pika also lives in its own burrow system, but unlike the arctic type, it lives a solitary life on what would be considered a home-range most of the time. During their active summer months they display very few signs of territoriality, but as they begin stockpiling food for the winter they adopt a feeding-only territory. They construct their "haypiles" (Dearing, 1997), placing them at several entrances to the burrow, and defend these caches until the time comes to retire to the burrow for the winter. 

WHY??

   These pikas also face intense predation pressure, hence, the burrow remains a vital unit to survival. Since their population densities are lower than that of the arctic pika, the defense of an abundant resource is even more unnecessary. It is only during the stockpiling time, at the end of the summer, that defense of caches becomes important. The amount of food in the caches is what determines survival over the winter, so making sure that other pikas don't take their food is essential. Hence, feeding-only territory.

* juvenile pika 

Mating System

   The mating system of the arctic-dwelling pika is one based on facultative monogamy. In most burrow families there is a breeding male and a breeding female who create a bond for an entire breeding season. They have up to 3 litters a year and all of the offspring remain on their natal home-range (Smith, 1991). They both care for the young equally.

   Though this is the norm, these pikas can exhibit mating strategies ranging from monogamy to polyandry in any given year. It has been hypothesized by Smith and Xue Gao (1991) that the system employed is dependent upon the population constraints. If there are few available female mates, than monogamy is the ideal. If there is an excess in females, than males will try to hoard extra females into their home-range.

WHY??

   There are a few points that are key in this discussion. First, the family unit is an important source of warmth in the burrow. The more children you have the better. In order to have children in your burrow you have to have a female that is generally monogamous with you. This is one of the main reasons monogamy evolved in the first place. Second, males are almost always looking for extra-pair copulations. The only time they don't is when there is a shortage in females and they have to spend all of their time defending their mate. Third, research on these little guys is not very extensive. The articles that pertain to mating in the arctic-dwelling pika were few and far between, hence very conclusive ideas cannot be made. The important aspect here is that if other mating systems occur in the pika, it is all derived from the monogamous framework.

   The talus-dwelling pika is far simpler; they exhibit overlap promiscuity. These pikas home-ranges overlap considerably (during the non-haying season), but interaction with others is minimal. During the breeding season, a male and female of overlapping home-ranges will join, mate, and then they will go there separate ways. The males exhibit no parental care, leaving it to the female (Svendsen, 1979). But females show an "absentee maternal care system" (Whitworth, 1984). Young are weaned by the 6th week. 

WHY??

   The question here should be why not? Promiscuity is very cost efficient. There is no need to waste energy guarding a mate if that mate gives you no advantages. The advantage of a mate in the other pika is that it guarantees a warm den. In the talus dwellers, warmth in the den is not as important, so having kids to keep you warm isn't necessary. Also, with such low population densities, the need to guard a female is not as important, because there aren't as many males around to sneak copulations.

Social Cooperation/Altruism

   The only form of cooperation that pikas exhibit is calling. They have an unusually large vocal repertoire for a lagomorph. This is used in a variety of contexts. In the arctic-dwelling pika there are many calls associated with the juveniles and their needs: hunger calls, cold calls, and injury calls (Conner et al. 1985). But the cooperation has to do with alarm calling. All adult pikas alarm call. In the arctic morph this call is meant for the family unit. It is cooperative because by alerting family members to danger, the caller ensures that all those whom he/she shares genes with survives. These calls are often followed by increased alertness in the young, and often by juveniles fleeing towards a burrow hole.

   In the talus-dwelling pika the alarm call is not meant to warn others, but to let the predator know that he has been spotted. This is evident by the fact that these pikas will selectively alarm call, depending on the predator. Some predators rely on stealth, so if they are spotted, their chance of catching anything to eat is minimal. So by calling the pika lets the predator know " I see you". But if the predator is one that relies more on speed (per say) than the pika just gets down and hides. The idea hear is that the individual making the call doesn't care about the other pikas in the area. They are not related, so the caller gains nothing by warning the others.

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

Works Cited

Connor, Douglas A. and Whitworth, Molly R. 1985. The ontogeny of vocal 

        communication in the pika. Journal of Mammalogy, 66(4): 756-763.

Dearing, Denise M. 1997. The Function of Haypiles of pikas (Ochotona princeps). 

        Journal of Mammalogy. 78(4): 1156-1163.

Smith, Andrew T. and Gao, Wang Xue. 1991. Social relationships of adult        

        black-lipped pikas (Ochotona curzonaie). Journal of Mammalogy. 72(2): 231-247.

Smith, Andrew T., Smith, Harriet J., Gao, Wang Xue, Xiangchu, Yin, and 

        Junxiun, Liang. 1986. Social behavior of the steppe-dwelling black-lipped 

        pika. National Geographic Research. 2(1):57-74.

Svendsen, Gerald E. 1979. Territoriality and behavior in a population of pikas 

        (Ochotona princeps). Journal of Mammalogy. 60(2):324-330.

Whitworth, Molly R. 1984. Maternal care and behavioural development in pikas 

        (Ochotona princeps). Animal Behavior. 32:743-752.