[2] The word was introduced in 1930 by Karl Max Schneider, director of the Leipzig zoo and an authority on big cats in captivity.
[5] This response is characterized by the animal curling back its top lip exposing the front teeth and gums, then inhaling and holding the posture for several seconds.
The VNO is found encompassed inside a bony or cartilaginous capsule which opens into the base of the nasal cavity.
[6] Animals that exhibit flehmen have a papilla located behind the incisors and ducts which connect the oral cavity to the VNO, with horses being an exception.
Sources of non-VOCs relevant to the flehmen response include pheromones and hormones excreted from the genital regions or urine of animals.
[19] Elephants perform a flehmen response but also transfer chemosensory stimuli to the vomeronasal opening in the roof of their mouths using the prehensile structure, sometimes called a "finger", at the tips of their trunks.
[citation needed] Other animals which exhibit the flehmen response include sheep,[12] American bison,[20] tigers,[21] tapirs,[22] lions,[23] giraffes,[19] goats,[24] llamas,[25] kobs,[26] hedgehogs,[27] rhinoceros,[28][29] giant pandas,[30] antelope[10] and hippopotamuses.