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

Daniel Heuclin / Panamint rattlesnake (Crotalus stephensi) with tongue out and rattle raised, on rock. Amargosa Desert, Nye County, Nevada. May.

Daniel Heuclin / Panamint rattlesnake (Crotalus stephensi) on rock, tongue out and rattle raised. Amargosa Desert, Nye County, Nevada. May.

Felis Images / Bengal tiger (Panthera tigris), walking on track, tongue out, tasting air in flehmen response. Ranthambore National Park, India. Photo Phillip Ross/Felis Images

Tony Wu / Ezo red fox (Vulpes vulpes schrencki) sitting on snow, licking lips after eating Vole. Hokkaido, Japan. April.

Andy Rouse / Bengal tiger (Panthera tigris) female showing flehmen response to detect scent on air. Ranthambhore National Park, India.

Andy Rouse / Bengal tiger (Panthera tigris) female showing flehmen response to detect scent on air. Ranthambhore National Park, India.

Andy Rouse / Bengal tiger (Panthera tigris) cub standing, licking lips. Ranthambhore National Park, India.