Anyone who is a fan of the classic Nintendo game Pokémon (or anyone who has been a child in the last 20 years) is familiar with the (fictional) electricity-shooting super-rodent, Pikachu. What many super-nerds may not be aware of is that the very real animal, on which the famous pocket monster is based, lives right here in the Yukon.
Collared pika — sometimes called whistling hares, because of their distinct, bird-like alarm call — are small, mouse-like mammals that make their home among rock piles in northern alpine environments, specifically in boulder fields above the treeline.
Pika are grey-brown in colour, with large, rounded ears, small eyes, long whiskers, chubby bodies and short, bobbed tails. These little fellows grow to be between 15 and 20 centimetres long and weigh around 160 grams, around the same size as a rat. While Pika appear to closely resemble rodents, they are actually members of the rabbit family, says Tom Jung, a senior wildlife biologist with Environment Yukon.
Collared pika are “from a Canadian perspective, a Yukon species,” says Jung. Aside from a smattering in northern British Columbia and the Northwest Territories, the Yukon is where most of Canada’s collared pika reside, although the species is prolific in Alaska.
It is closely related to the American pika, which inhabits a range spanning the Canadian Rockies all the way to New Mexico. Similar to northern-ranging Dall sheep and their more southerly cousins, bighorn sheep, collared pika and American pika probably split off from one common ancestor, becoming separate species as the distance between the northern and southern populations increased.
Despite being absurdly adorable, collared pika are exceptionally hardy, resilient animals. They act a bit like farmers, with specific “harvest seasons,” says Jung, which means the majority of their food must be gathered in the short alpine summer months, between July and September.
Pika eat mostly grasses, which they collect in caches — called hay piles — and store away from the naturally occurring rock piles (called taluses) where they live. Pika don’t hibernate, Jung notes, but remain active beneath the snow which covers their rock piles during the cold months, and so they have to work extra hard to get enough food to last them all winter in a relatively short period.
Pika are territorial, asocial animals, says Environment Yukon wildlife technician Pila Kukka, and will chase off other pika who get too close to their homes, especially if they are of the same sex. Pika mate in May, usually with the member of the opposite sex closest at hand, and give birth to two or three offspring after around 30 days, usually in mid-July, she says.
While the babies are born blind and hairless, they grow quickly, Kukka says, and they don’t overwinter with their mothers. This means they have to begin to care for themselves — including finding their own home and building their own haypile for winter — “basically as soon as they are weaned.”
Pika are extreme “homebodies,” says Jung, preferring to stay as close to their talus as possible, where they are protected from predators such as red foxes, eagles and ermines. Unfortunately, the plants they dine on grow in open alpine meadows, which means a pika must constantly be weighing the danger of being eaten against the threat of not having enough to eat.
“The life of a pika is measured in risk,” says Jung. “They’re very averse to leaving their rock piles.”
This trait means that collared pika essentially form pocket populations, Jung says. They do not like to travel into new territories and so are very slow to colonize new ones. This means there is very little interbreeding happening between populations separated by any significant distance. Pika even evolve different “dialects” of calls, with different accents among individual populations.
“Pika who live in Kusawa have very little genetic flow with pika who live in Kluane Park,” Jung says.
This is important to consider in terms of conservation, Jung says. If a population experiences a localized extinction — say, by a climate event or disease outbreak — then that genetic set is permanently lost. Likewise, it would take a long time for other populations to step in to fill the ecological niche the lost population leaves behind.
“Pika in Kluane could take a long, long time to recolonize an area in Kusawa,” he says.
Furthermore, Jung says, pika are vulnerable to climate change, inhabiting “a very narrow niche” in their ecosystems. They cannot tolerate temperature of higher than 27 C, he says, and rising climates are pushing treelines higher, pinching off their ranges.
Warmer weather also means more snow in the mountains, which actually delays spring because it takes a longer time to melt, shortening the harvest season for pika. Pika are presently listed as a “vulnerable” species in the Yukon, largely for this reason, he said.
Pika are actually the first animal in Canada to be listed as at-risk specifically due to climate change, he says.
“The Yukon is actually a pretty dry place,” says Jung. “Now, with climate change … the snow lasts longer, and that’s a problem for pika.”
“This is the new norm…. There’s a concern pika can’t adapt.”
Environment Yukon is currently conducting a population survey of collared pika in Tombstone National Park, Kukka says. There is “lots of variability” in pika population depending on the year, she says, and there was was a “noted decline” in the Tombstone population last year which might be weather related.
Non-scientists — such as hikers using the park — are adding to the study data base, she says, by helping to identify areas where the pika live and counting them, something that’s simple to do because pika have such a distinct call and their rock piles are easily identifiable.
“We can sample more sites (when people participate) this way,” Kukka says.
Contact Lori Fox at lori.fox@yukon-news.com