The lip-curl or flehmen response exposes the vomeronasal organ to scent molecules. This organ, also called the Jacobson’s organ located in the roof of the mouth is extremely sensitive, allowing bucks to determine a doe’s state of estrus.
While bucks will occasionally lip-curl at other times of the year; during the rut it is very common
No photo series of the whitetail rut is complete without a good buck, in good light, posed against an attractive background. This year I have been blessed.
The images posted here were captured in Shenandoah National Park, a place where wild creatures are able to live out their entire natural lives with little to no fear of humans. Only in places like this where there is no nearby agriculture, human habitation, or high-speed roads can whitetails be allowed to exist in this manner. For the wildlife photographer these are places to be treasured.