Emanuele Biggi / Northern spectacled salamander (Salamandrina perspicillata) displaying unkenreflex in response to threat, Savignone, Italy.

Emanuele Biggi / Northern spectacled salamander (Salamandrina perspicillata) displaying unkenreflex in response to threat, Licenza, Italy.

Sergey Gorshkov / Siberian tiger (Panthera tigris altaica) grabbing tree in forest with paw and rubbing against it, before laying down and displaying Flehmen Response, Land of the Leopard National Park, Russian Far Eas...

Sergey Gorshkov / Siberian tiger (Panthera tigris altaica) displaying Flehmen Response and rolling in leaves in front of scent marked tree in forest, Land of the Leopard National Park, Russian Far East. Endangered. Tak...

Joel Sartore / Photo Ark / Belitung island tarsier (Tarsius bancanus ssp. saltator) turning head and moving ears in response to sound, private collection, Jakarta, Indonesia. Captive.

Nick Garbutt / Male Exmoor pony (Equus ferus caballus), semi-feral native breed, sniffing the air, flehmen response to female scent, Exmoor National Park, Somerset / Devon, England. November.

Nick Garbutt / Male Exmoor pony (Equus ferus caballus), semi-feral native breed, sniffing the air, flehmen response to female scent. Exmoor National Park, Somerset / Devon, England. November.