Grzegorz Lesniewski / Brown Bear (Ursus arctos) sharpening its claws on a tree. Bieszczady National Park, the Carpathians, Poland, April.

Mitsuaki Iwago / African Lion (Panthera leo) female sharpening claws, Serengeti National Park, Tanzania

Duncan Murrell / A Batak woman with her child in a sling sharpening a knife in Sitio Kalakwasan in Cleopatra's Needle Critical Habitat, Palawan, the Philippines.

Philippe Clement / Lynx (Lynx lynx) sharpening claws on tree trunk before walking away, Germany, May. Captive

Edwin Giesbers / Lynx (Lynx lynx) stretching and sharpening claws, Germany, July. Captive.

Philippe Clement / Lynx (Lynx lynx) stretching and sharpening claws on fallen tree trunk, Isselburg, Germany, October. Captive.

Francois Savigny / Male Bengal tiger sratching tree {Panthera tigris tigris} Bandhavgarh NP, India - sharpening claws and marking his territory

Christophe Courteau / Lion (Panthera leo) male sharpening his claws on a tree at night, Sabi Sand Game Reserve, South Africa.

Nick Garbutt / North American bobcat (Lynx rufus) scratching / sharpening its claws on fallen tree trunk. Madison River Valley, Yellowstone National Park, Wyoming, USA. January

Yukihiro Fukuda / Feral domestic rabbit (Oryctolagus cuniculus) sharpening claws, Okunojima Island, also known as Rabbit Island, Hiroshima, Japan.

Cyril Ruoso / Domestic Cat (Felis catus) sharpening its claws on a tree, France

George Sanker / Black bear (Ursus americanus) sharpening its claws on a tree trunk. Yellowstone National Park, Wyoming, USA, June.