Elk NetworkThe Rut

Conservation | July 24, 2017

As Autumn dabbles in her paint box to frost the early mornings and tinge the woods with red and gold, I am sitting on a piney hillside, just listening to the hush. I shove my hands deep in my jacket pockets and scrunch my chin into my collar to hoard a little warmth. My breath puffs out little clouds into the chilly air. A jay calls, and a pine cone thumps to the ground. Then, piercing the quiet, a high far trumpeting squeal wails over the hills, sending prickles up my neck. And another squeal answers. This one a little closer and louder, ending in a belly-deep e-uh! e-uh! e-uh!

The rut is on.

It’s easy to think that the elk rut is all about big, bugling bulls. After all, they put on quite a show as they flaunt their size and racks, clash with challengers, and herd cows into harems. Yet the rut is ultimately about creating the next generation of spring elk calves. And all that showing off is really for the gals, who take their pick of the best bulls. But we’ll come back to that in a minute.

Perfect Timing

Have you ever wondered why elk breed in the fall when so many other animals breed in spring? It is critical that calves be born just at the peak of spring growth, when new grasses and forage will give them the best start on a summer of feeding and growing. Like other big animals, elk have long pregnancies. They have adapted to the long winters of northern climates by growing their calves slowly during pregnancy, so the cow will have plenty of energy to survive the winter herself. For elk, it takes about eight and a half months to grow a calf to size before birth. That pushes the breeding season back to the first weeks of autumn.

Big, Bad and Stinky

A bull elk during rut spends most of his energy trying to broadcast just how big and superior he is. The biggest bulls are in their prime at 6 to 8 years old. Everything about a bull’s display during rut advertises his fitness as a mate and his toughness as an opponent. A bulls’ rutting behavior sends several messages. First and foremost the bull is trying to attract cows. But he also hopes to discourage weaker bulls from challenging him.

The size of a bull’s antlers shows his age and his success at foraging and survival. Perfectly matched and symmetrical antlers also show off how healthy he is. If his antlers are crooked or misshapen, he may be sick, have parasites or be injured. Genetics, old age and poor nutrition may also cause a bull to have abnormal antlers.

A bull advertises his size and dominance to cows and rival bulls through his bugle. The bigger the bull, the deeper and louder he can bugle. Think of a trumpet compared to a flute. The high frequency of an elk’s bugle can also carry far over open country— the kind of prairies and savannahs elk evolved in. Red deer in Europe and Asia have a lower frequency bugle, called a “roar,“ that travels better in thick forest. The belly-deep grunt at the end of an elk’s bugle also shows off his size, and seems designed to advertise to cows nearby.

A big, confident bull will spend a good deal of time rubbing trees, wallowing and flooding the area with his scent. Bulls spray themselves with urine, soaking their belly, chest and mane. Our noses may not appreciate such elk perfume, but in the animal world, scent is like advertising with billboards and flashing neon signs. To a bull, spraying himself with urine is like putting on his coolest clothes. Horning trees and wallowing in mud spreads his scent even farther.

Picky, Picky

As a bull tries to charm females into his harem with all of his bugling and display, it’s the cows that are sizing up the bulls in the neighborhood and deciding who looks most attractive. A cow is after two things. She wants to mate with the bull that will give her the healthiest calf. She also wants to escape being harassed by younger bulls that constantly try to chase down unattached females, so she can spend her time feeding for the winter ahead.

A large bull’s display not only attracts cows, it also helps keep them in the harem. The more he advertises, the less likely the cows will leave him. A bull will also herd females to try to keep them from escaping to a rival. He will cut off a cow that has ventured too far away, rushing at her and sometimes jabbing her with his antlers. Cows do break away if they really want to, but because a big herd bull also keeps younger bulls at a distance, staying in the harem of a larger bull gives a cow some peace.

Once a cow comes into heat, the bull’s courting behavior is very different from his herding behavior. He doesn’t rush at her. Instead, he approaches slowly and directly, with antlers high and tongue flicking, doing everything he can to win her over. If a cow isn’t ready to mate, she moves away holding her head low, weaving her neck side to side as if to say “stop,“ and the bull breaks off his courting. Once a cow is ready, however, she will tolerate the bull’s approach.

Challenge

A bugling bull also attracts other large bulls who may try to fight for his harem. Bulls will avoid a fight if they can. They show off, as if to convince the other to quit. They march side by side, bugle at one another, and thrash the ground and small trees with their antlers. If an older bull confronts a young or more timid male, this is usually enough to convince the youngster to retreat.

More evenly matched bulls will readily fight. After sizing each other up, the bulls lock antlers and begin to shove one another in a test of strength. Each tries to get the uphill position to gain the advantage of gravity. Usually these fights are short but exhausting. The weaker bull will give up and flee, trying to turn away fast enough to avoid being gored by the winner. The winner then follows after the loser and bugles. Sometimes fights do go on and on, and though fights are rarely lethal, if a bull loses his footing, he can be gored to death in seconds.

By the end of the rut, a bull will carry antler wounds from many battles. He will be exhausted from displays and challenges, and from weeks of eating little. As winter’s first snows swirl down, the bulls move off alone to heal and feed to regain enough strength to survive the coming months. The hills fall silent. In another year, that fine high trumpeting call will sound, and the show will begin again.