Orsolya Haarberg / Grey alder trees (Alnus incana) cut and gnawed by Eurasian beaver (Castor fiber) Telemark, Norway, July

Orsolya Haarberg / Grey alder trees (Alnus incana) cut and gnawed by Eurasian beaver (Castor fiber) Telemark, Norway, July

Yva Momatiuk & John Eastcott / Snowshoe Hare (Lepus americanus) with summer coat beside gnawed park sign, Denali National Park, Alaska

Martin Gabriel / Tree gnawed by Eurasian beaver {Castor fiber} Bavaria, Germany.

LYNN M. STONE / American beaver at gnawed tree trunk {Castor canadensis} Minnisota, USA Captive.

Michael Quinton / Arctic Ground Squirrel (Spermophilus parryii) gnawed sign, Denali National Park, Alaska