A small high-altitude mammal that most literally “makes hay while the sun shines” is the Collared Pika (Ochotona collaris). These unique animals inhabit the rocky talus slopes of mountains in central and southern Alaska and are the northern representatives of a genus that is distributed throughout the Rocky Mountains, Cascade ranges and California. The pika is the smallest of the lagomorphs, a taxonomic group that includes hares and rabbits. In some places pika are commonly called “rock rabbits” or “little chief hare.”
At first glance, which is about all one gets of them dashing about in the wild, they appear to be more closely related to guinea pigs than rabbits. They are small robust mammals with short ears, short legs, and no external tail. The hind feet are not much longer than the front feet and their heads look elongated. They are about 7 inches long and 3 inches high and have a pelage like that of hares and rabbits. Unlike the marmot, another small mountain mammal with a whistle-like call, the pika doesn¹t hibernate. Because they do not hibernate, they must store food for winter. They dash back and forth between the talus slopes and the meadows where they forage, returning each time to their hay piles near the center of their territories with mouthfuls of flowers and grasses. In the meadows, pikas literally mow down plants, turning their heads to the side to bite off stems as close to the ground as possible.
They engage in two distinctly different types of foraging behavior: haying (collecting food for storage) and grazing (eating on the spot). Studies suggest that they divide their trips about equally between the two activities but found that haymakers tend to harvest stalks, leaves and blossoms of flowers, while grazers tend to munch on grasses (perhaps, as folks who mow their lawns know, because grass is a constant renewable resource). Pikas tend to select plants in a definite sequence through a season. They will select for nutritional value, harvesting plants with relatively high caloric protein or fat content. Also,during the flowering season, some plants protect their leaves and stems with poisonous chemicals, but later in the summer the plant stores the toxins in its root system. That way, the plant doesn¹t have to go to the effort to remanufacture the toxins in the spring – when the seasonal growth once again is vulnerable to haying pikas.
Consequently, these plants get passed by in their early flowering stage but will likely be harvested later, after the toxins recede back into the roots by the haying pikas. The haystacks may contain as much as a bushel of vegetation, cached under an overhanging rock to protect it from rain and snow. One study found that pikas choose some plants that inhibit bacterial growth and act as a hay-pile preservative. Pikas preferentially hayed Alpine avens, a species toxic to pikas, apparently the plants preserve the hay piles, then the pikas later consume the avens after the toxic chemicals degrade. Hay piles are not only critical for pika¹s winter survival, they also enable the pikas to reproduce when their alpine meadows are still snow-covered. Births of litters, usually triplets, tend to occur as snow melts in spring and a flush of growth transforms high alpine meadows into hayfields. The new food, along with stored fat, helps mothers ensure that their young are weaned successfully, leaving both adults and their offspring with as much time as possible to gather new hay piles to sustain them through the next long, hard winter. The young weigh about 1/3 of an ounce at birth and the mother has a 30 day gestation period. The youngsters grow quickly and are weaned when they are only about one- third grown.
Females may sometimes breed again, producing two litters in one season. Their grass lined nests are hidden deep in rock crevices, unavailable to most predators other than the smaller weasels. The ermine and avian predators such as golden eagles are their main predators. They spend considerable time sunning themselves, hunched up on a prominent look-out rock. When frightened, the pika quickly drops off its look-out rock and scuttles between the rocks. One of the many interesting features of this little creature is its call – a nasal bleat which has a ventriloquial effect that seems to be heard from several directions. It takes some time and effort to locate the little pika, perched on a rock some yards away, often in plain view. With each call its head jerks upwards and its mouth opens momentarily to expose the curved needle-like lower incisors. They normally live in colonies, but each animal has its own turf so the colony is dispersed across a rock slope. Males and females defend individual territories of about equal size, which may be as large as 750 square yards, using urine-anointed scent- posts, lookouts, and haystacks to delimit their territories. Their little bleat or bark may also be used as a warning to possible trespassers. Population densities may be in the order of six pikas per acre of talus slope.
The next time you venture into alpine habitat, look for an animal that has the body of a guinea pig, the face of a rabbit, the ears of Mickey Mouse, and the voice of a squeaky toy. You may have the pleasure of viewing one of Alaska¹s most entertaining little mammal.