What about the early and late ruts? Hunters often talk about the rut being early or late. In much of Texas at least, the breeding season for white-tailed deer is fairly predictable each year. Within a specific area, habitat conditions not only affect fawn survival, but can affect the timing of breeding as well. For example, a doe in poor condition (not enough deer food)or a young doe may not breed until late in the season. In addition, 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 a low number of bucks compared to does, 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 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 biological reasoning helps explain the wide variety of opinions on the timing of the rut during a particular year. (more…)

In some circles, you will still hear people talk about the old barren doe that lives in a particular part of the ranch. This line of thinking blames poor fawn production on the idea that many older does do not get pregnant. In reality, if the doe isn’t bred during the first estrous period, she will be receptive again 28 days later. This explains the high breeding success in white-tailed deer, even when bucks are scarce. It was recorded in one Texas study, that on average, 92 of every 100 does sampled were pregnant.

White-tailed deer are known for producing twins. In the previously mentioned study, over half of the does examined had twins. Triplets, however, were not common, and the occurrence of triplets was less than two percent. Quadruplets didn’t show up at all in the study. There were more male fetuses than female fetuses. Males represented 56 percent of the unborn fawns over the three years of the study.

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It was once thought that large, mature bucks dominated the breeding in deer herds. The premise was that the largest individuals would successfully defended all receptive does (does that are in estrous) from other bucks in the area. Of course, genetic testing came along and that allowed researchers to identify what exactly is happening out there in the woods. During the breeding season whitetail bucks search for individually receptive does. And understand this, it is not uncommon for a buck to court a doe for up to a day prior to her being receptive and then breed her repeatedly over the 24 to 36 hours (while she is in estrous).

The buck then searches for another doe and repeats the process. Therefore, bucks that successfully breed may spend as much as 24 to 48 hours with a single doe before looking for another. Due to the time spent with an individual doe, and because the most does in a balanced population are bred over a relatively short time frame, a single buck just can not monopolize the breeding.

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