On pikas and ticks

Abstract

The pika (Ochotona princeps) is a lagomorph that typically lives in rocky areas such as talus slopes, at elevations of 8000 to 13,000 feet in the Rocky Mountains of western North America. As the climate warms, species from lower elevations can shift their range upwards, but most pika populations have nowhere to go because they already live at the highest elevations (eg J Mammal 2020; doi.org/10.1093/jmammal/gyaa110). Range shifts of species from lower elevations might also harm pikas. In October 2020, one of us (Olmstead) photographed this pika near Silver Lake in Big Cottonwood Canyon, in the Wasatch Range within Salt Lake County, Utah. Numerous engorged ticks (species unknown) are evident in the lesion on its throat, and others appear to be around its ear. Johanna Varner, a pika expert at Colorado Mesa University (Grand Junction, CO), remarked: “None of us [referring to herself and other authorities] have ever seen a pika with so many ticks on it: in fact, your pika had more ticks on its cheek and ear than I’ve seen on all pikas combined in my 10 years of watching them!” Various tick species have expanded their ranges as the climate has warmed. If these and other ectoparasites become more prevalent in alpine zones, then the health of alpine wildlife populations, such as those of the already vulnerable pika, could be adversely affected.