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 populations in the southwestern United States are declining due to habitat loss and global warming.
[7] However, the American pika is overall considered a species of Least Concern, and is still common in the northwestern United States and Canada.
American pikas, known in the 19th century as "little Chief hares",[8] have a small, round, ovate body.
[11] The dorsal fur of the pika ranges from grayish to cinnamon-brown, often colored with tawny or ochraceous hues, during the summer.
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.
[13] 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).
[11] American pikas rely on existing spaces in the talus for homes and do not dig burrows.
It eats a large variety of green plants, including different kinds of grasses, sedges, thistles, and fireweed.
Lactation significantly reduces a female's fat reserves and they only wean the second litter if the first does not survive, despite exhibiting postpartum estrus.
[10] Predators of the pika include eagles, hawks, coyotes, bobcats, mountain lions, foxes, and weasels.
In warmer environments, such as during midday sun and at lower elevation limits, pikas typically become inactive and withdraw into cooler talus openings.
[16] Because of behavioral adaptation, American pikas also persist in the hot climates of Craters of the Moon and Lava Beds National Monuments (Idaho and California, respectively).
[22] Recent studies suggest some populations are declining due to various factors, most notably global warming.
[20] A 2003 study, published in the Journal of Mammalogy, showed nine of 25 sampled populations of American pika had been extirpated in the Great Basin, leading biologists to conduct further investigations to determine if the species as a whole is vulnerable.
[23] In 2010, the US government considered, then decided not to add the American pika under the US Endangered Species Act.
[3] The Pikas in Peril Project,[25] funded through the National Park Service Climate Change Response Program, began data collection in May 2010.
A large team of academic researchers and National Park Service staff - from three universities and eight national parks - worked together to address questions regarding the vulnerability of the American pika to future climate change scenarios projected for the western United States.
[26] More recent studies have found widespread extirpations and range retractions at lower elevations which are typically warmer and drier, patterns that have been further attributed to varying aspects of climate change such as warmer summer and winter temperatures and changes in precipitation.