By Alexus Berndt and Stephanie Schuttler on November 18 2016
The phrase stuck in a rut describes a “blah” feeling we endure when our life is monotonous, unchanging and lacking in excitement. Summer is over, the days are getting shorter, and you may be feeling like you’re stuck in a rut. Did you know that deer all across our state have fallen in a rut too? Their experience is very different, defined by fights and excitement, rather than boredom.
The white-tailed deer (Odocoileus virginianus) typically begins its mating season, otherwise known as rut, in October. Rut can begin as early as September and depends on daylight, a doe’s health, and the local environment. Day length is an important external cue that may make us sleepier, but initiates the physiological process of the estrous cycle in female deer. Most females go into heat in November for a short twenty-four hour period and will go into a second heat approximately twenty-eight days later if they have not mated. Therefore, an interested buck has to act fast, and indeed deer are more active during this time. In a recent eMammal study, we found deer vigilance, as measured by how frequent the deer the deer keeps its head up, increased over the fall season and was not related to hunting, meaning that deer may have been searching for mates as the rut progressed.
Rut is defined by the dramatic fights that bucks engage in to win females. Bucks use their antlers for matches against other males to win the territory with the best does for mating. Bucks need to choose their matches wisely; if they choose an opponent that is too strong, the consequences can greatly impair their health or even lead to death. But if they don’t take risks, then they will not be able to mate and therefore pass on their genes. Males that are older, larger, and more experienced tend to be the most dominant and are able to win the most females. Males that win, and are able to defend that territory, will then be able to mate with that female. They will also try to expand their area to include the family group and therefore more mating opportunities. Males are polygamous, meaning they will mate with several females throughout the season.
If a female is in poor physical health, their estrous cycle may be delayed for a month or in more extreme cases, even a year. Females typically begin mating in their second year, however females will mate as early as seven months. The local environment and herd conditions are also key factors in determining the timing of the rut. Rut will occur later in environments with little nutritional forage and where herds are largely skewed towards females because many females will not breed until later cycles due to competition. Therefore, rut may be happening in the early fall in the north, but may not start until later for southern states.
Next time you’re feeling the need to hibernate with the decreasing daylight, remember that for deer it is the most exciting time of the year!