The Whitetail Deer Rut

It’s that time of year again. Whitetail deer are on the move as the annual rut, or mating season, starts to heat up. Sometime around early November, love begins to fill the air as females, or does, come into heat and buck testosterone levels rise. Does have already dispersed this year’s buck fawns in order to mate again, and eager one- and two-year-old bucks in particular—I call them teenagers—are the first to show any interest. This can set the stage for some challenges when older, more experienced bucks eventually step into the picture when the time is right.

Fawn dispersal plays an important role in whitetail deer procreation dynamics because it prevents potential genetic integration by related deer—known as inbreeding—from entering the gene pool. After nearly six months of motherly love, the doe gives any buck fawns a kick and chases them away, which forces them to look for other territories of their own.

Females come into heat every 28 days, beginning in November. In most years, breeding takes place during the first half of the month and nearly all adult does are bred then. Those that aren’t will be ready to mate again in early December when a second, less significant rut occurs. It can continue into January in the unlikely event that any doe remains un-bred. In a case where a doe isn’t bred until the second or third rut, it also means a later birthing period will occur the next summer. The whitetail deer gestation period is about 200 days.

A whitetail doe only comes into estrus for a period of 24 to 36 hours, which is the only time that she will be receptive to a buck. Unlike a bull elk, which accumulates a harem of cows to breed, a whitetail buck only stays with one doe at a time, which—judging by her estrus aroma—could last as long as 72 hours. Then he’ll move on to search for another.

But it’s also that time of year again for an increase in deer/vehicle collisions as well. More deer are hit between mid-October and mid-December than at any other time of year—and it is entirely because of the rut. Bucks chase does and does run from bucks and all normal whitetail caution is thrown to the wind. During most of the year, deer move mostly during the dawn and twilight hours. During the rut it can be at any time of the day or night—so be forewarned.

adamski_profile_Apr21Story and photo by John Adamski

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