function of both a defensive mechanism and a warning signal against predators. As a collared pika prepares to call, it sits with a hunched back and points its nose upward. Collared pika calls sound like a recurring single sharp note with each series varying in loudness and is similar to the American pika’s short call. When interacting on a territory, collared pikas use a softer call than their normal vocalizations. Both males and females can emit vocalizations from some sort of fixed position within their home ranges, especially during the period of gathering. This territorial call informs neighboring collared pikas of haypile possession. Adult males specifically have their own call that sounds like a strong series of “kie” calls and clicking during mating season. Population and conservation status The estimated population density is roughly around 6.4 to 7.2 individuals per hectare. In various regions of the Yukon, the range is around one to four pikas per hectare. Both collared pikas and American pikas are commonly believed to be philopatric species. In addition, research data have shown that young collared pikas rarely disperse over 300 m away from their original den, and adults hardly ever leave an established territory. No population trend is known, but the population of collared pikas has experienced a decline since 1995 in the Yukon area, and is proposed to have a higher probability of extinction within that specific area in 10 to 15 years. Due to collared pikas being a cold-adapted species, their resilience to climate change is limited, so they have a high risk of extirpation of any populations found at lower altitudes and lower in latitude. Consequently, collared pikas have been recognized as an indicator species for the effect of climate change on alpine ecosystems. Lifespan The lifespan of O. collaris can be up to 7 years in the wild. The mortality rate is high during winter and they have suffered from a continuous reduction of population over time. The struggle to survive the winters and the fast-rate climate variations have affected their growing season and availability of resources, especially from the negative impact of not having snowpacks to keep them insulated or to keep their food and shelters hidden from predators. Predation Collared pikas are defenseless against predators and can only hide within cracks or crevices in the mountainous areas where they live; the rocks of the terrain are their only shelter. One