According to a fascinating article put out by Dr. Karl V. Miller from the University of Georgia, few hunters know that a deer actually has two ‘noses‘.\
“The second nose is technically not a nose, but it serves some of the same purpose. If you look on the roof of the deer‘s mouth, you will see a diamond shaped structure with a small passage leading into the palate. This additional nose, called the vomeronasal organ (VNO), is similar to the Jacobson’s organ that snakes use to ‘taste’ the air. Deer use the VNO exclusively to analyze urine. When a buck sees a doe urinate, he will often take some of this urine into his mouth and perform a behavior called flehmen, or lip-curl.”
“This flehmen helps to introduce urine into the VNO. It is interesting that this organ is not connected to the same part of the brain that the nose is connected to. Instead, it is connected to the part of the brain that controls the reproductive condition of the deer. What type of information the deer is getting is unknown, but it is likely that odors analyzed in the VNO help get the hormones pumping in the buck and bring him into rutting condition.”
That nose comes in handy for dodging predators but it also is key during the rut when bucks are smelling their way to does in estrus.
According to Texas Parks & Wildlife Department study, a doe may be attractive to bucks for about five days, but may be willing to breed for a period of only 24 hours. If the doe is not bred during her first cycle, she will generally come into heat again about 28 days later.”
“In areas where there are few bucks, a doe may not encounter a buck when she is first receptive and may not be bred until one of her later cycles. A hunter, landowner or biologist who sees the late breeding activity may be convinced that there was a late rut. On the other hand, those who see does attended by bucks in the early part of the season believe there was an early rut. This helps explain the wide variety of opinions on the timing of the rut during a particular year.” Bucks however don’t care about schedule. All they focus on is catching a smell f of a doe in estrus and know they will stop at nothing to breed her.