Chasing the Rut

Stepping out into the pre-dawn darkness, my breath hangs in the air, momentarily frozen in time. There’s the sting of cold on my face. The burn of my hands. It’s not like Yellowstone in the winter, with minus 40-degree temperatures that reaches deep inside your chest and steals the oxygen from your lungs, but it’s enough to let you know that it’s here, a time of change.

The Canadian Rockies are different. They’re younger, sharper, steeper, more dramatic, and more glaciated than their southern counterparts. This region is properly boreal, where aspen and paper birch mix with spruce and firs, where great gray owls and woodland caribou still haunt the shadows of the forest.

For many years before moving to Alaska from Montana, I would make an annual pilgrimage to Alberta, Canada. Packing my old Land Rover, I would shove camping gear next to pelican cases filled with camera equipment and pull out onto interstate. North was the new west.

My itinerary was always the same. I like my back roads, especially in Montana where speed limits on two lane roads are faster than four lane interstates in the east. You can drive for hours without passing another vehicle sometimes. The route for me was always the same: 287 north to 89 – that super scenic highway of the west. From there I skirted the eastern edge of Glacier National Park before jumping the border at the Chief Mountain Port of Entry. Then it was on to Calgary, Banff, the Icefields Parkway, Jasper.

This business of heading north might seem strange given that I was living in Montana and surrounded by the lion’s share of charismatic megafauna in North America. I had ready access to seven different species that descended into the madness we call the rut, and would fight to the death for the right to breed. But the nature of making a living as a wildlife photographer is a peculiar thing.

This habit of traveling to Jasper National Park began with an email from a magazine editor. It was simple and to the point. “I need more photos of elk.”

A fair request, or demand. No problem for me, of course. I lived in a landscape largely denuded by elk after nearly a century of being overpopulated thanks to the absence of wolves on the scene. So, I replied with a link to a lightbox of curated photos of elk for her to choose from. The response? “No. I have these. I need new ones.”

It was with that email I realized it had been a few years since I had concentrated my efforts on the elk rut. Moose? Yes. Mule deer? Absolutely. But making a living as a wildlife photographer is all about being able to keep producing. Though my archives were full of sellable images of elk, I like to devote myself completely to a particular subject or species at any given time. While I had been investing myself in other animals the last few years, those photos of the elk rut had been published enough times on the magazine market that they were of little interest outside of the wholesale stock agencies like Getty Images. So, I did what any self-respecting wildlife photographer who needed images of elk would do in a pinch: I drove to Rocky Mountain National Park in Colorado.

But upon arriving, it was immediately obvious this was not going to work. Unless you have been hiding under a rock, or living in a highly controlled urban environment where you never go outside, you may have picked up on the fact that things aren’t quite like what they used to be. Here it was the last week of September, the absolute statistical peak of the elk rut across North America, and temperatures were in the upper 80s in the mountains of Colorado.

While the timing of the rut occurs at the same time every year, temperature plays a big role in what you see. Bison and pronghorn are little different in this respect because they evolved in a landscape of tremendous temperature swings and have a hypothalamus that helps regulate body and brain temperature differently than other species. But for the rest of the big ungulates that experience the rut each year, the muskox, moose, elk, caribou, white-tail and mule deer, bighorns and the thinhorns, temperatures above the mid-50s shut down behavior. There are a few exceptions to this based on geography, but by and large if the temperatures are rising above 54° F (12° C), everything you hope to see, and photograph, will be confined to the dark of night when it’s the coolest.

For me, this meant the most I could hope for from Colorado was a bull elk laying in the shade trying not to die of heat exhaustion.

So, I drove north from one elk rut photography hotspot to the next. Jackson Hole, Yellowstone, Slippery Anne (Montana), the east side of Glacier National Park, Waterton Lakes National Park in Canada, and on to Banff. Still, the rut was being impacted by high temperatures that confined activity to night.

Upon reaching Jasper National Park, however, I immediately recognized things would be different. I had driven through snow flurries along the Icefields Parkway, and descending into the valley I noted the temperature gage on the dash of my vehicle read 34°F. The Fall colors were still at peak and the almost eerie sound of bugles, both battle cry and love song of bull elk, reverberated throughout the forest.

I had driven over 1,500 miles in search of an elk rut to photograph. Sure, I had the directive from an editor and visions of cover shots dancing in my head (when an editor contacts you for a particular shot, it usually means they are looking for an important component of the magazine). But let’s face it, the time and money and effort to travel the spine of the Rocky Mountains across two countries in search of elk photos couldn’t be justified by the possibility of a single cover sale. No, there was only one word that could explain this: obsession.

A whitetail buck on the Colorado prairie with the Front Range in the distance. Photographing during the rut isn’t just about capturing images of males locked in dubious battle. Instead, it’s about working with animals when they are in their prime, when they are the biggest, the most regal, the most photogenic, and the most preoccupied with other things.

The impact that the rut has on those individuals who participate cannot be overstated. Everything that makes a bull moose a bull moose is, in large part, thanks to the rut. This is both natural selection and sexual selection. If you want to breed, if you think you have what it takes to pass on your genetic legacy to posterity, then you must be willing to gamble with your life.

While there are a couple outliers here, most species experience the rut in the autumn, when temperatures are dropping, and winter is on the horizon. During the rut, males all but cease to eat. As a result, a bull elk will lose 20% of his body weight in just four short weeks. This means a thousand-pound animal will lose two hundred pounds in a month’s time. That’s just an average. More dominant males, with larger harems of cows to protect, lose more body mass because they engage in more fights than other males.

Then, of course, there are the inevitable consequences of all those battles. Males sustain countless wounds during the rut. Sometimes it’s in the form of a broken rib. Sometimes it’s the loss of an eye (I can’t begin to count the number of elk, moose, and whitetail deer I have photographed who were blind in one eye from previous fights). Other times animals are peeled open along their flanks from the tine of an antler of an opposing male - as was the case with one of my favorite bull moose in Grand Teton National Park.  

And even if a male survives the rut, there is no guarantee they won’t succumb to those wounds over the coming weeks or months. Right when every other animal in the ecosystem is desperately trying to prepare for winter, for the inevitable cold and lack of food and the many unknowns during the frozen months, those species that engage in the rut stop eating entirely, they begin fighting, fretting over mates, losing significant amounts of body fat that would otherwise protect them through the lean times of winter, and begin sustaining wounds that may prove fatal.

If you have ever wondered why there are more females of these species than males, this is it, this is why. Fawns and calves are born at equal ratios, 50% males and 50% females. However, by the time those animals reach sexual maturity, the population becomes dramatically skewed. And on average, by sexual maturity 70% of a population of these species tends to be females and only 30% (or less) are male.

This is the consequence of the rut.

Likewise, if you have ever wondered why so many of the photos you see of wolves on an elk kill in the winter are bull elk with massive antlers sticking up from the snow, it’s for this reason. In fact, the wolves of Jasper National Park and Yellowstone National Park specifically target bulls with their winter hunting strategies simply because of generations’ worth of accumulated knowledge that large bulls are often the ones who are the weakest and hobbled by injuries come winter.

And it’s all because of the rut.

The rut is like natural selection in overdrive. In any herd of American bison, for instance, genetic studies show that 50% of the calves each year are sired by one single bull. Many bison will never breed, will never sire offspring, and their genetic line will die with them. Only the biggest, the strongest, the most cunning, the most genetically fit will leave their legacy upon the next generation. We use terms like survival of the fittest when we speak of evolution and the rut puts all of that thinking on display.

For hooved mammals across the globe, death is always at the heel. All ungulates are prey. And the evolution of large predators happened in lockstep with these animals.

Consider the gray wolf again for a moment.

To understand how the rut is important to the survival of North American elk, for instance, we must first toss out all the old lies and mythologies and fables concocted about wolves. When we peel back the layers of culturally imposed perceptions of these animals, and we look only at the science of wolf predation, the elegance of the rut begins to take shape.

First there is the strategy of the hunt. A bull elk who is willing to stand their ground is unlikely to become wolf food. I have watched elk and moose quite easily fight off entire packs. I have watched a lone cow bison kick and stomp and jump and buck and spin only to send 19 wolves trotting away empty handed.

But if they run, it’s a completely different story.

Wolf packs want their prey up and moving. Their strategy is to sew chaos, to intimidate and pressure a herd to run. It’s when an elk is running that their biography is on full display for a pack of wolves. Who’s fast and who’s not? Who’s weak, old, injured, infirm, or young? A herd on the move allows a pack to scrutinize every individual and make calculated risk-reward decisions.

An eighty-pound wolf, the average size for Yellowstone National Park, is no match for a thousand-pound bull elk in his prime. A well-placed kick results in broken limbs or ribs for a wolf. These, in turn, are a death sentence to a predator in the wild. And it’s for this reason that the hunting strategy for a pack of wolves is to push a herd of elk to run, to flee, because it’s then that the low-hanging fruit can be singled out.

Studies of wolf kills in Yellowstone National Park during the winter, the season of the wolf, reveal trends. For years, Doug Smith, the head researcher who oversaw the reintroduction of wolves in the park, would cut open the bones of elk that wolves had killed to assess the physical fitness of the individual. While something of a gruesome task, this research quickly revealed that most elk taken by wolves had no marrow left inside their bones. Bone marrow contains large reserves of fat. The absence of marrow in the bones of wolf killed elk meant that those individuals were quite literally starving to death when the wolves killed them; the elk had already consumed all the reserves of fat on their body and were absorbing the very marrow in their bones to stay alive.

Look at it this way: while both winter and wolves work in tandem to cull herds of elk, it’s the rut, that self-imposed selective pressure that ensures only the best, the strongest, the genetically fittest, are breeding to ensure that elk as a species are prepared and always two steps ahead.

For all the hype about big males locked in dubious battle during the rut, at the end of the day it’s still the females who choose their mates.

Females of all ungulates undergo their own trial by fire through the process of bearing and raising offspring. Their bodies must be in peak physical condition to carry a calf or a fawn through winter; they must have the ability to find and store enough fat for themselves but also enough to produce milk. Then they must protect that calf in a landscape filled with predators for whom young animals are at the very top of the menu. This is no easy task. And the simple act of bringing the next generation into this world is enough to ensure only the genetically fittest females succeed.

The rut crams all the physical demands a cow or a doe must go through for many months into just a few short weeks for males. Those who come out on top will be selected by females to mate with. Those who survive the months of deprivation and predation afterword will have the opportunity to do it all over again.

Despite popular misconceptions, the rut doesn’t change timing. Just because the availability of food may change year to year, or the fact that one year is dryer or wetter, or colder or warmer, the timing stays the same.

While the timing of the rut for an individual species is predicated upon their length of gestation, the trigger that creates that hormonal switch in males is the ratio of daylight to dark. For those ungulates who experience the rut, bison have the longest gestation period in North America while bighorn sheep have the shortest. Therefore, it’s no coincidence that bison begin rutting in late summer while bighorns start banging heads on the doorstep of winter.

Whether bison or bighorn, everything is timed perfectly so that in the spring all these different species in the ecosystem give birth at roughly the same time. While there is a measure of getting the timing right so offspring can prepare for the inevitable winter ahead in places like Wyoming and Montana, this behavior is seen across the planet where multiple species of ungulates live side by side even in the absence of what we might consider “real” winter. Instead, this synchronous calving season, so the leading hypothesis goes, is an attempt to flood the landscape with babies all at once to dilute the impact of predation. The carrying capacity of an ecosystem for large predators is finite. The number of predators in any given area can only eat so many babies in the two to four weeks it takes for those babies to be strong enough and fast enough to keep pace with mom and outrun predators.

Thanks to the different lengths of gestation amongst ungulates, the rut, in North America at least, is a six-month long ordeal. Beginning with bison, the torch is then passed on to the likes of muskox, then pronghorn, and on to elk, moose, and caribou. Come November, white-tailed and mule deer join the fray. And by the beginning of December, the wild sheep of North America, both bighorn and thinhorn (Dall and stone) are doing battle.

This is six months of action for the ambitious wildlife photographer, six months of non-stop opportunities to photograph the charismatic megafauna of the continent in their prime, when males are the biggest, the most photogenic, and so completely drunk off their testosterone so as to drop their guard around humans and other predators.

For all wildlife photographers around the world, the breeding season presents opportunities not found at any other time. Whether you photograph birds in Australia or fireflies in Asia, elephants in Amboseli or moose in Denali, that time of year when the males of the species are giving it everything they have to look their best, stand out from the crowed, and do what it takes to win the hearts and minds of the ladies, it’s these times of the year when memory cards are easily filled. And for the big ungulates of North America, much like Eurasia and Africa, the rut is the universe’s gift to wildlife photographers.

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