The Truth About Antler Genetics, Timing the Rut and Whitetail Glands

Scientists believe individual deer have unique scent profiles, so when they use these glands to make a rub or scrape, it’s like leaving a fingerprint at a crime scene. Photo: Reconyx

How much do you really know about antler genetics, the rut and whitetail glands? Even if you think you know the truth, you might not. And, to put it bluntly: If you’re not right, you’re wrong. So, let’s test your knowledge and get the cold hard facts about these topics from Kip Adams, wildlife biologist and chief conservation officer for the National Deer Association.

Fact or Myth:

Hunters can heavily influence antler size by shooting cull bucks and bucks with an unfavorable rack.

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Don’t waste your time trying to influence antler size by shooting cull bucks. Instead, focus on the two things you can impact: age and nutrition.

MYTH! Although genetics is one of the three factors (in addition to age and nutrition) that influences antler growth, it’s the less effective variable to control. Manipulating genetics to produce large racks works in captive deer herds because people can carefully pick bucks to mate with specific does, but it doesn’t work in the wild. Here’s why:

1) Dominant bucks can’t dominate the gene pool because they’re often with one doe when it’s in heat. Since most does in an area come into heat during a two-week window, a dominant buck simply doesn’t have enough time to breed every doe nearby, especially if he’s locked up with one specific doe for the 24 to 36 hours that she’s in heat. That scenario allows other bucks – often less dominant bucks – to find and breed does. The rut is an intense, crazy time. Bucks will likely come from miles away to breed, while dominant bucks are occupied. Adams said it’s a “Johnny on the spot” situation. Small bucks will breed does, regardless of your efforts to stop them.

2) Hunters can’t accurately predict the antler size of a buck’s offspring by simply looking at the father’s rack. Research shows big bucks sire fawns with much smaller antlers, and small bucks sire large-antlered offspring. A buck’s rack size doesn’t indicate what size rack its offspring might have, especially because does are 50% responsible for a fawn’s genetics and 100% responsible for the fawn’s maternal care. So, does play a slightly bigger role in antler growth because they provide their offspring with adequate – or inadequate – nutrition. Designating and killing cull or small bucks is pointless because these bucks might have the genetics, but might not have received sufficient nutrition to reach their antler potential.

“There’s nothing we can do from a genetic standpoint (to affect antler growth) in a wild deer herd,” Adams said. “Conversely, there’s a lot we can do for the other two factors. We can let deer get older so they can express a lot more of their genetic potential, and we can make sure they have good habitat so they can get the nutrition they need to express more of that antler growth potential.”

Don’t waste your time, bullets or broadheads. Instead, focus on the two things you can impact: age and nutrition. Learning how to properly age whitetails on the hoof will help you identify young bucks so you can avoid shooting them. That ultimately allows them to grow bigger headgear. Additionally, using mineral sites, creating food plots, and planting fruit and nut trees can help provide adequate nutrition for ideal whitetail antler growth.

Fact or Myth:

The whitetail rut always happens in early November, regardless of the region.

Whitetail deer rut
The majority of whitetail breeding and rutting behavior across the U.S. happens over a short window from early to mid-November, but there’s an exception.

MYTH! Most of this statement is true because the majority of whitetail breeding and rutting behavior across the U.S. happens over a short window from early to mid-November, but there’s an exception.

The Southeast. “There are numerous different rut times that happen from Florida up through the Gulf Coast into some southeastern states,” Adams said. “If you’re a rut hunter and you chase the rut, you literally can start hunting Florida in July and hunt a rutting population of whitetail deer somewhere in the Southeast right on into February.”

What causes the odd rut timing in southeastern states? Adams said mild winter conditions and restocking efforts from the early 1900s are to blame. From an evolutionary standpoint, all animals adapt to their environment to survive. It makes biological sense for northern deer to breed at a specific time in fall so their offspring drop at a specific time in spring.

Does in northern states go into estrus and are bred in early to mid-November to ensure fawns are born in April when it’s not too cold and there’s plenty of food. If a fawn is born too early, there might not be enough greens to eat. Conversely, if a fawn is born too late, they won’t have enough time to bulk up before winter. Both cases result in high fawn mortality.

Southeastern whitetail populations aren’t confined by the same environmental factors like harsh winters and short growing seasons. Therefore, they have wider breeding windows. To find the peak rut in your region, observe when fawns drop and count back 200 days (a whitetail’s typical gestational timeframe) to determine when the doe was bred.

A Bonus Rut

Adams said many midwestern hunters talk about a second rut. They say it usually occurs in December or January because some does weren’t bred the first time. But according to Adams, a second rut can occur when fawns that dropped in the previous spring become sexually mature. This doesn’t happen often, but if it does happen, it’s an indication of quality habitat and abundant food sources in your area. Fawns must be in good health (at least 70 or 80 pounds) to mature and breed early. If it happens near you, Adams said this timeframe can offer “the most dynamite hunting action of the whole year.” This bonus rut marks a time when bucks want to breed, but only a small number of deer are in estrus.

Fact or Myth:

Whitetails use their glands to communicate with other deer.

FACT! Adams said does have six glands, and bucks have seven. Both sexes have three on their head and three on their legs. The extra gland on a male is in their crotch. Scientists don’t know exactly what each gland is for, but they do know a few things from what they’ve studied.

Infographic courtesy of the National Deer Association.

First, does and bucks rub together – and pee on – their tarsal glands. Located on the inside of their hind legs, these glands are used to communicate with other deer via scent. Second, does and bucks will rub their forehead glands against trees and branches. This represents another way deer communicate aromatically. Scientists believe individual deer have unique scent profiles, so when they use these glands to make a rub or scrape, it’s like leaving a fingerprint at a crime scene. The culprit’s identity is unmistakable.

Deer agitate and use these glands year-round to communicate, but gland usage increases during the breeding season to help find a suitable, receptive mate.

“Deer rub these glands to leave information about themselves like their nutritional status, dominant status and identity, and to advertise their presence for other deer in the area to come and check out,” Adams said.

As a hunter, you can work your way into the conversation by using deer attractants and scents. This strategy might help you intercept deer communicating with other deer in the area.

Final Takeaway

There’s a lot of false information floating around the web. Achieving total control of a wild deer herd is impractical and impossible. However, understanding factual concepts and doing your part to properly manage land and whitetail populations will help improve the quality of hunts on your property.

Featured photo courtesy of Reconyx game cameras.

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