Inside the Mind of a Rutting Buck

Article and photos by MATT BUCKINGHAM

Getting inside the mind of a rutting buck is pretty simple—it’s on a single track and everything else—eating, sleeping, everything—is pushed aside. Getting to that ultra-focused, one-track state, however, doesn’t happen overnight. It all starts when the velvet is shed. As the days shorten and the temperature cools, this furry tissue that has nourished growing antlers for the previous six to seven months begins to dry and the underlying bone hardens. Like a boxer pulling off the gloves, those fuzzy strips dropping to the ground signal to other bucks that the time for friendship will soon end. A time for battle is coming.

The white-tailed deer (Odocoileus virginianus) is arguably the most familiar, revered mammal in the country. Deer have fascinated nature lovers and outdoorsmen for generations. The whitetail is the widest ranging ungulate in the western hemisphere and can be found from central Canada to Peru. They are incredibly adaptable and can often be found thriving in areas with dense human populations.

While does can approach a buck, more often than not it is the buck that will pursue the doe, advancing toward her with his head lowered, communicating his clear intention to mate.

White-tailed bucks leave lots of sign during the rut. When a hunter sees a fresh scrape, it’s clear a rutting buck is close by. Both scrapes and rubs are common signs of rutting activity.

Despite their abundance, mature bucks, especially those trophy class individuals, are elusive and seldom seen—like phantoms of the wood and brush, which only adds to their mythos. While the whitetail remains one of the most recognizable species in the country, few outside the world of hunters and biologists understand the incredible life history of this emblematic species. The most fascinating component of this life history may very well be the annual rut.

Shedding velvet must make the bucks itch fiercely, as they furiously thrash their antlers against any available vegetation to speed up the process. As it is stripped from bone, the velvet hangs from the antlers in a bloody mess until it is completely removed.

After the velvet is shed, the bucks will begin to spar, their weapons ready—hard and sharp, rising from their skulls like a crown of blades. Initially the matches are friendly and no real effort is made to harm one another. The camaraderie will soon end, however.

During the rut, bucks that are normally mild-mannered and tolerant of one another turn violent and aggressive. A sudden and dramatic increase in testosterone fills them with lust and rage as they prepare to compete in an ancient breeding ritual—the culmination of a year spent eating, growing, and preparing. During this time, they will fight, sometimes to the death, to carry on their bloodlines.

To truly appreciate the rut’s ecology, consider its timing. Initially, it seems counterintuitive. It is well known that during the rut, bucks barely eat, barely sleep, and expend a seemingly insane amount of calories as they cover vast distances, run down does, and engage in all-out brawls with other bucks.

In fact, a buck may lose 25% or more of its body weight in a matter of weeks. To top things off, this happens right before the leanest time of the year, when food will be in short supply, bucks will be more exposed, and predators are looking for an easy meal. In the context of evolution, it appears to make no sense.

In truth, there is good reason, evolutionarily speaking, why the rut occurs when it does, and it all has to do with fawns. The white-tailed deer’s gestation period is a bit over six and a half months. For a fawn to be born sometime in late May or early June, the doe would need to have been bred sometime in November.

The rut’s timing works in tandem with the does’ gestation period, and results in fawns being born when, at least during normal years, forage production is ramping up. This ensures ample nutrition for milk-producing does and hungry fawns. In much of the country and a good swath of the Lone Star State, this period occurs in the late spring or early summer.

The precise timing of the rut varies. For example, along the Upper Texas Coast, where spring comes a bit earlier and nutritious forage begins to emerge sooner, the rut may peak in mid- to lateSeptember so that fawns are dropped earlier the next year. In South Texas, where vegetation growth is often fueled by summer rainfall, the rut peaks later

Bucks will frequently visit antler-height branches and take small twigs in their mouth. They lick them and rub them against special glands on their face known as pre-orbitals that leave pheromones for other deer to detect. Commonly known as “licking branches,” it is believed that these whitetail message boards are used to communicate important information in the white-tailed deer community.

Bucks will pursue as many does as possible during the rut. This buck is stalking “the one,” head down and intense on his work.

so that fawns may drop during the second half of July to take advantage of rain-fueled, forage-producing plants.

In the weeks after their velvet has been shed, bucks that spent the spring and summer lounging and feeding together begin to grow intolerant of each other’s presence and isolate themselves in the brush. The sudden flush of testosterone facilitates rapid muscle growth, and as the bucks violently thrash the brush around them and rub the bark from trees and shrubs, their neck muscles swell to an intimidating size.

This new musculature is not simply for show. It will serve them well during the upcoming combat. The bucks also become bolder during this time, and as they move about their territories searching for does, they become more active during the day and are easier to observe and less prone to flight. They truly have one thing on their mind.

Around the same time, the does are becoming reproductively receptive and communicate their impending estrus through pheromones in their urine. They advertise their fertility by moving through the brush and leaving their chemical signature on the landscape.

The bucks also leave abundant sign. They will frequently visit antler-height branches and take small twigs in their mouth. It may appear as if they’re feeding, but they’re not actually eating the twigs. Instead, they lick them and rub them against special glands on their face known as pre-orbitals that leave pheromones for other deer to detect.

Commonly known as “licking branches,” it is believed that these whitetail message boards are used to communicate important information in the white-tailed deer community, including the status of a buck among the herd. Bucks visiting the licking branch can quickly ascertain what other bucks are in the area, and therefore evaluate threats to their ability to defend and breed a doe.

Does, too, will use the licking branch, likely to determine which bucks may be nearby, and advertise when they are approaching estrus, that brief window when they are fertile.

Occupying such an expansive range means there is considerable variation in white-tailed deer throughout their distribution. Those at the northern extent of their range are generally the largest bodied. Following Bergmann’s rule, they become gradually smaller moving south. There are exceptions to this, however, and local populations may be larger or smaller based on a variety of factors.

Antler size is less predictable. It is highly variable and more closely linked to local genetics and available nutrition than thermoregulatory requirements.

In addition to scrapes, rubs are another indication that bucks are around. They’ll rub on branches and small trees as they shed their velvet, and violently thrash as testosterone levels spike.

Bucks will fight with an awesome intensity. And there’s no crying Uncle. When the loser tries to break away, the victor will pursue, raking the loser’s flanks.

South Texas brush country deer, for example, are world famous for their impressive headgear. The larger-than-average antlers of mature bucks in the region have been attributed to a number of factors, including the protein-rich bounty of prickly pear, mesquite beans, and other foods found here. South Texas is also known for its heavily managed deer ranches, where selective harvest enhances genetics and supplemental feed bolsters nutrition.

Both body and antler size are important. While the largest-bodied bucks in an area often will sport the largest antlers, this isn’t always the case. A large rack likely serves to both intimidate rivals and attract does. Large, symmetrical antlers communicate the buck’s genetic quality, and does innately favor those bucks that will provide the highest quality genes to their offspring. When push comes to shove, however, it is typically superior body size over impressive headgear that will win a fight.

Spurred by increased testosterone levels, bucks seek outlets for their increasingly violent tendencies and begin to thrash vegetation, including low-hanging guarding her before he can breed her and seek another partner.

Bucks determine which does are approaching estrus through a process known as lip curling, or flehming. The strange crinkly-nosed face they make is known as the Flehmen response. When a buck detects the scent of a doe’s urine, he will curl his upper lip back and pass the pheromone-laden aroma through the vomeronasal organ in the roof of his mouth.

Typically, a flehming buck will cock his head back 45 degrees or so. Perhaps this maximizes the organ’s ability to analyze the pheromones. It’s not uncommon to see a buck move his head up and down and from side to side during this process, as if trying to find the sweet spot for extracting doe pheromones from the air above her spoor. The response may last several seconds.

If all goes well with the Flehmen response, a buck can determine which does are nearly ready to breed. If he detects the pheromones of “the one,” he will seek her out. The plan is to find her and tend her until she comes into estrus, during which time he intends to copulate with her as many times as possible to ensure conception and chase off any rivals that may get the wrong idea.

A particularly receptive doe may entice a buck by initiating a game of cat and mouse, where she runs seductively to and fro in an attempt to illicit a chase response. More often than not, however, it is the buck that will pursue the doe, advancing toward her with his head lowered, communicating his clear intention to mate.

He will often emit a series of grunts during this pursuit. Does that are not yet receptive or unimpressed with their suitor will spurn his advances. A buck guarding a doe will make several of these “buck runs” until he receives indication from the doe that she is ready to breed. The strange, crouched trot of the buck during this behavior is often referred to as “bird-dogging.”

In a perfect world, there would be plenty of does for all, and every buck would have equal opportunity to pass on his genes.

branches and tree trunks. Beyond serving as an outlet for their energy, these rubs, like the licking branches, serve an important purpose during the rut. The rub’s height and the destruction it caused can communicate the buck’s size and strength to would-be competitors.

It is also believed that bucks secrete additional pheromones as they rub and that seeing a mature buck turn a small tree or shrub to pulp provides an intimidating warning to younger bucks. After depositing his scent on a licking tree or creating a rub, a buck will typically dig a “scrape” by hoofing at the dirt and urinating over the metatarsal gland on his hind leg, further leaving his mark across the landscape.

As the does near estrus, the bucks really begin to take notice. Chemicals in a doe’s urine contain information as to her current stage in the reproductive cycle. Every buck is driven to breed as many does as he can during the rut, so this information helps him determine which lovely lady he should pursue. An experienced buck will focus on those does that are very near estrus so he can minimize the time spent

Bucks will often posture when they first meet a rival. But when horns clash, the combatants come together with a crash. Bucks will fight to exhaustion, even to the death.

That’s not the way things work, however, and competition for breeding rights is fierce. It is in a doe’s best interest to be choosy when it comes to a suitor so that she may ensure her offspring have the best genetic blueprint for survival and success in life.

It is also in the buck’s nature to breed as many does as he can, maximizing the continuation of his bloodline. When the stakes are this high, conflict is bound to arise.

A fight is inevitable when two evenly matched bucks come face to face and neither is willing to back down. Even so, they will exhaust every option before engaging. First, a buck may communicate his displeasure with an opponent’s presence by forcing air through his nostrils and emitting a long, hissing sound known as a “wheeze.” It may occasionally be preceded by two shorter exhalations, in which case it is commonly referred to as a “snort-wheeze.”

On a rare occasion, a buck may also communicate his displeasure toward a hunter or photographer in this manner. When wheezing fails, the bucks will approach one another in a ritualized manner, pinning their ears back, opening their eyes wide and causing the hairs in their pelage to stand erect. This clearly signals that things are about to get physical.

And when they do, it can be explosive—white-tailed deer are famous for the intensity of their battles. They may ease into it at first, slowly maneuvering their antlers into place before initiating a bout of pushing. In other cases, it begins with a CRACK when one buck lunges forward, head down, and the other is forced to catch him with his antlers.

Once entwined they put everything they have into attempting forward motion, trying to throw their opponent off center and gain the upper hand. They may disengage and re-lock their antlers several times in a fight, and tines may snap and skin may tear. Often, one buck will be forced to the ground, and he better regain his feet quickly.

During these fights, the bucks are quite literally trying to kill one another; given the chance, that’s exactly what they will do. Once the victor is clear, the loser beats a hasty retreat, often with the winning buck at his heels, goring at his flanks. These battles are often decided in a minute or less, but occasionally they can go much longer, and leave in their wake a trail of trampled vegetation, tufts of hair, and spatters of blood. Look closely at a buck during the rut and you may see that his antler tines are tinged red.

Strength and experience generally determine the outcome of these skirmishes. For this reason, older, larger bucks tend to breed more does. Of course, it’s not just the big bucks that are driven to breed during the rut. The urge to procreate is strong, and younger and smaller bucks are not spared the lust. Their path may be more difficult, but the dominant bucks can’t be

Does that are not yet receptive or unimpressed with their suitor will spurn his advances. A buck guarding a doe will make several of these “buck runs” until the doe indicates she is ready to breed. The buck’s strange, crouched trot during this behavior is often referred to as “bird-dogging.”

In addition to leaving a lot of scent signals that a buck is defending does, they’ll warn other suitors away with sound. A buck may communicate his displeasure with an opponent’s presence by forcing air through his nostrils and emitting a long, hissing sound known as a “wheeze.”

everywhere at once, and when they are busy guarding a doe or fending off incoming suitors, these “satellite” bucks are often able to sneak in and mate with some of the does in their territory.

The rut lasts for a month or more, with a peak activity period of around 10 days sometime in November or December throughout much of Texas. However, activities may begin as early as September along the Upper Coast and continue as “late” as January in deep South Texas.

On average, a female is only in estrus for 24 hours or so, providing a limited window where fertilization can occur. Those does that are not bred during the first cycle will come into estrus a few weeks later. This, combined with a few does that come into heat early, may prolong the rut. But any way you slice it, it is but a small, albeit supremely important portion of a deer’s annual cycle.

Of course, this is just a small snippet of all that occurs during the rut. However, understanding the behaviors of the rut is important to anyone who wishes to pursue whitetails during this time, be they hunters, photographers, or nature enthusiasts hoping to catch a glimpse of one of the natural world’s great spectacles.

With that said, it is also important to consider that no two bucks behave the same during the rut. Some bucks tend to travel great distances in search of “hot” does, while others may stick to a small core area and tend the does that appear there. Others may remain strictly nocturnal while some may become bolder and move from early afternoon to late morning.

To successfully see bucks during the rut, spend significant time patterning them before peak rut. Place trail cams to track their movements and look for sign such as rubs and scrapes during the early stages of the rut. Numerous resources exist to help track the projected rut dates across Texas.

Each year, I look forward to experiencing the white-tailed deer rut and have been privileged to witness many incredible behaviors over the years. The fabled whitetail may be the most famous, revered, and sought-after animal in North America. It is so popular, common, and widespread that it oftentimes fades into the background for naturalists and wildlife photographers.

But I can attest that those who put in the time and effort to learn their ways and experience their world will be greatly rewarded. From the pine-hardwood forests of East Texas to the riparian woodlands of the Panhandle and Trans-Pecos, and the thornscrub of South Texas, may the white-tailed deer continue to dig scrapes, lock antlers, secure their bloodlines, and capture the hearts of millions in the Lone Star State and beyond for generations to come.

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