"The Rut" is the period of time when antlered ungulates, such as deer, sheep, elk, moose, caribou, ibex, goats, pronghorn and Asian and African antelope, mate. The rut for white-tailed deer usually lasts from 1-3 months in the northern hemisphere and may occur most of the year in tropical zones. The Rut is triggered by a shortening of the length of daylight hours (referred to as photoperiod) each day. The dates of the rut for different species depends on the length of the gestation period (length of pregnancy) for each species. Many species breed so that their young are born in the spring, shortly after new green growth has appeared (which provides food for the females so they can provide milk for the young) and when the temperatures are warm enough so the young will not die of hypothermia.

The Rut is the time when white-tailed deer (Odocoileus virginianus), especially bucks, are more active and less cautious than usual. This makes them vulnerable and more easily hunted as well as more susceptible to being struck by motor vehicles. Some people believe that the white-tailed deer rut is also controlled by the lunar phase and that the rut peaks seven days after the second full moon (the rutting moon) after the autumnal equinox on September 21st. However, a white-tailed deer doe conception dates study conducted in Minnesota between 1980 and 1987, and first compared to the phases of the moon by researcher T.R. Michels, and later confirmed by a student study at the University of Georgia, showed no correlation between peak breeding dates of white-tailed deer and any lunar phase. Lunar phase refers to the appearance of the illuminated portion of the Moon as seen by an observer, usually on Earth. ... Illumination of Earth by Sun on the day of equinox The autumnal equinox (or fall equinox) marks the beginning of astronomical autumn. ...

Many scientists have compared this phenomenon to what is otherwise known as "balling" or "flying high" (as it is known in the African-American community). There has been a recent crack-down on 'rutting in public places', otherwise known as RPP infractures. Rutting in clubs especially has come under fire for violating the Rutting Protocol Standards of 1970, as spelled out in Senate Resolution 32456.

The rutting period is a reflection of all mammalian sexual enticement and attraction to the opposite sex. All people metaphorically rub antlers on trees? Some scholars such as Hank Ostenberg("Honky life" 2003) have sugested the deer as a superior candidate for survival due to its sheer horniness and perserverance of the female deer's punami. It could be speculated that the deer in rut is like a drunken 21 year old at the bar scheming on the oldest fattest sleeziest easiest shorty at the bar (Ostenberg 2003).

A whitetail doe may be in estrus for up to 72 hours, and may come into estrus up to seven times if she is not bred. Cow elk may come into estrus up to four or more times if they are unbred. It should be noted that the Irish ritual of mating is somewhat similar to the primal mating ritual of the common deer. The nipple rubbing common in most Irish immigrant native of south eastern americans (southside richmond) is an example of how nature prevails even in the most ostensibly civillized asexual beings (Donkulus 2006).

During the rut (also known as the rutting period) males (buck deer, bull elk and moose, ram sheep and male goats) often rub their antlers or horns on trees or shrubs, fight with each other, and pursue estrus females by their scent.