Silke Arndt / Western rattlesnake (Crotalus viridis viridis), threat display, South Dakota, USA, September.

Claudio Contreras / Grey fox (Urocyon cinereoargenteus) licking nose, captive, Mexico City

Anup Shah / Long-tailed macaque (Macaca fascicularis) juvenile sticking tongue out. Khao Sam Roi Yot National Park, Thailand.

Mark Taylor / Red toy poodle looking up at camera an sticking out tongue.

Staffan Widstrand / Polar Bear (Ursus maritimus) head portrait with blue tongue sticking out, Svalbard, Norway

Andrew Walmsley / Mini lop-eared domestic rabbit with one ear up and one ear down, and tongue sticking out, Captive, Christchurch, New Zealand

Rolf Nussbaumer / Head portrait of Gulf Coast Ribbon snake (Thamnophis proximus orarius) covered in duckweed and swimming, with tongue protruding, Fennessey Ranch, Refugio, Corpus Christi, Coastal Bend, Texas Coast, U...

Andy Rouse / European otter (Lutra lutra) on riverbank, sticking out tongue, captive, UK

Kim Taylor / Common European Toad (Bufo bufo) female sticking out tongue to feed on mealworm, Captive, UK,

Kim Taylor / Common European Toad (Bufo bufo) female sticking out tongue to feed on mealworm, Captive, UK, sequence 2/3

Kim Taylor / Common European Toad (Bufo bufo) female sticking out tongue to feed on mealworm, Captive, UK, sequence 2/3

Anup Shah / Golden langur {Presbytis geei} sticking its tongue out, India