Flehmen response

(Sumatran Tiger shown)]] The flehmen response (, ), also called the flehmen position, flehmen reaction, flehming, or flehmening (from German flehmen, meaning to curl the upper lip), is a particular type of curling of the upper lip in ungulates, felids, and many other mammals, which facilitates the transfer of pheromones and other scents into the vomeronasal organ, also called the Jacobson's organ.

Exhibition

exhibits the flehmen response by curling back her upper lip]] In the flehmen response, animals draw back their lips in a manner that makes them appear to be "grimacing" or "smirking". The action, which is adopted when examining scents left by other animals either of the same species or of prey, helps expose the vomeronasal organ and draws scent molecules back toward it. This behavior allows animals to detect scents, for example from urine, of other members of their species or clues to the presence of prey. Flehming allows the animals to determine several factors, including the presence or absence of estrus, the physiological state of the animal, and how long ago the animal passed by. This particular response is recognizable, for example, in stallions when smelling the urine of a mare in heat.

Cats, especially house-cats, exhibit a natural and very noticeable teeth-baring grin - the Flehmen response - in order to draw scent into the Vomeronasal organ. The organ and its purpose was discovered in 1813, although cat owners have always observed the behavior.

This behavior is not limited to predators. Horses have been well-known to exhibit flehmen response.

Physiology

The vomeronasal organ, also called Jacobson's organ, is a chemoreceptor organ believed to play a role in the perception of certain scents and pheromones. It is named for its closeness to the vomer and nasal bones, and is particularly developed in animals such as cats and horses. The organ is located on the roof of the mouth. In addition to house cats and horses, animals who exhibit the flehmen reaction include buffalo, tigers, tapirs, lions, giraffes, goats, llamas and kobs.

Similar responses

A grimace similar to the flehmen response may also be seen in association with pain. In horses, it is often associated with low-grade abdominal pain.

References

Further reading

Swaisgood, R. R., D. G. Lindburg, X. Zhou, and M. A. Owen. 2000. The effects of sex, reproductive condition and context on discrimination of conspecific odours by giant pandas. Anim. Behav. 60; 227-237.

Category:Olfactory system