The rut (from the Latin rugire, meaning "to roar") is the mating season of certain mammals, which includes ungulates such as deer, sheep, camels, goats, pronghorns, bison, giraffes and antelopes, and extends to animals in other groups such as skunks and elephants. The rut is characterized in males by an increase in testosterone, exaggerated sexual dimorphisms, increased aggression, as well as increased interest in females. The males of the species may mark themselves with mud, undergo physiological changes or perform characteristic displays in order to make themselves more visually appealing to the females. Males also use olfaction to entice females to mate using secretions from glands and soaking in their own urine. During the rut (known as the rutting period and in domestic sheep management as tupping), males often rub their antlers or horns on trees or shrubs, fight with each other, wallow in mud or dust, self-anoint, and herd estrus females together. These displays make the male conspicuous and aid in mate selection. The rut in many species is triggered by shorter day lengths. For different species, the timing of the rut depends on the length of the gestation period (pregnancy), usually occurring so the young are born in the spring. This is shortly after new green growth has appeared thereby providing food for the females, allowing them to provide milk for the young, and when the temperatures are warm enough to reduce the risk of young becoming hypothermic.
Cervidae
White-tailed deer
The rut for white-tailed deer (Odocoileus virginianus) usually lasts three weeks in the Northern Hemisphere and may occur most of the year in tropical zones. The rut is the time when white-tail deer, especially bucks, are more active and less cautious than usual. This makes them easier to hunt, as well as more susceptible to being hit by motor vehicles. Outdoors writer Charles Alsheimer has done research demonstrating the white-tailed deer rut is also controlled by the lunar phase and that the rut peaks seven days after the second full moon during October and November (the rutting moon), while elk begin rutting during the September equinox on 21 September. A white-tail doe may be in estrus for up to 72 hours and may come into estrus up to seven times if she does not mate. Cows may come into estrus up to four or more times if they do not mate. Some people believe that it is possible that does can enter a second estrus around 28 to 30 days from its first estrus if the doe isn't bred. There are also studies that show that some does actively participate in seeking out possible mates in areas where there are less males to increase the chances of finding males and being bred. The rut can start as early as the end of September and can last all the way through the winter months. Bucks usually begin this process when the velvet is falling off their antlers, and it can last all the way until they start to shed their antlers. The peak of the rut, however, is right in the middle. The average peak day for the white-tail rut in the U.S. is November 13. Around this period of time, the bucks and does are very active, with the rut in full swing. For a hunter sitting in a tree stand at this time of the year, it is not uncommon to see many deer pass through his specific area, due to other deer chasing others.
There are many behaviors a buck will exhibit during the rut. During pre-rut, bucks will spar with each other. Sparring is low-intensity aggressive behavior, involving mostly pushing and shoving. Bucks of different sizes will do this to each other. After pre-rut is finished, a buck will rub his antlers on a tree (thus making a "rub"), and make scrapes on the ground with his hooves: both of these are ways a buck will mark its territory and proclaim his dominance for other bucks to see. These activities are usually done at night. Bucks will make many different scent markings using different scent glands. These scent glands include pedal glands found between the toes, preorbital glands found in the corners of their eyes, tarsal glands found on the lower inside of their hind legs, and the metatarsal glands found in the outside hind leg between ankle and hoof. The deer spread scent from these glands by rubbing hooves during ground scrapes, rubbing faces on tree limbs, and urinating down legs. The most prominent behavior of all during the heat of the rut is fighting, where bucks show their true dominance to others. In fighting, bucks usually battle against similar-sized deer, and small bucks do not normally challenge mature large ones: more often than not, smaller bucks fear the more mature bucks and leave or avoid the dominant deer's territory. These fights can be long in duration with the winner getting the group of does. Some fights result in injuries with some resulting in death. Studies show that males of all age-classes increased their search efforts for mates during rut. According to the source, "One-year-old males seemed to invest less effort searching for females because movement rates (m/h) were 25–30% lower than in older males". This data indicates that the youngest males don't try as hard as older males to find a mate. The energy expenditure of chasing and fighting during the breeding season can result in a buck losing an immense amount of weight, with some research documenting losses of as much as 20% of body weight with some sources showing body mass losses of up to 30%. On average, a buck before breeding season can weigh up to 180 pounds (82 kg). After he has gone through the stages of the rut, he can lose about 50 pounds (23 kg) of weight, which is quite large, especially for only a few months of time. In the post-rut, a buck will need to replenish his body and catch up on the weight and energy he has lost.
Elk (Wapiti)
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