Mark Raycroft / Arctic Ground Squirrel (Spermophilus parryii), North America

Jim Brandenburg / Arctic Ground Squirrel (Spermophilus parryii) standing guard, Alaska

Michio Hoshino / Arctic Ground Squirrel (Spermophilus parryii) peeking out of its hole, Alaska

Danny Green / Arctic ground squirrel (Spermophilus parryii) portrait, Denali National Park, Alaska, USA, September.

Ingo Arndt / Arctic Ground Squirrel (Spermophilus parryii) hibernating in it's burrow, University of Fairbanks, Alaska, captive. It's body temperature drop as low as ?2.9 C (26.8 F) the lowest known naturally occu...

Ingo Arndt / Arctic Ground Squirrel (Spermophilus parryii) hibernating in its burrow / University of Fairbanks, Alaska, captive. Its body temperature can drop as low as 2.9 C (26.8 F) the lowest known naturally oc...

Ingo Arndt / Arctic Ground Squirrel (Spermophilus parryii) hibernating in its burrow, University of Fairbanks, Alaska, captive. It's body temperature drop as low as ?2.9 C (26.8 F) the lowest known naturally occur...

Ingo Arndt / Arctic Ground Squirrel (Spermophilus parryii) hibernating in its burrow / University of Fairbanks, Alaska, captive. Its body temperature drop as low as ?2.9 C (26.8 F) the lowest known naturally occur...

Matthias Breiter / Arctic Ground Squirrel (Spermophilus parryii), Hudson Bay, Manitoba, Canada

Matthias Breiter / Arctic Ground Squirrel (Spermophilus parryii), Hudson Bay, Manitoba, Canada

Matthias Breiter / Arctic Ground Squirrel (Spermophilus parryii) with wildflowers, Hudson Bay, Manitoba, Canada

Loic Poidevin / Arctic ground squirrel (Spermophilus parryii) Katmai National Park, Alaska, USA, August