All ungulates, and some other mammals such as horses and donkeys, exhibit abehavior called flehmen or lip curl. Without a sound, they open their mouths and pull their upper lips back after smelling the urine of another individual. Males are testing whether the urine is from a female in heat. Only during the initial period of the estrus cycle, when the female is ovulating, will most mammals, including elk, mate. Just before sunrise thislarge bull was walking behind a group of cows and tested the urine of one of the cows. He held his nose high, for about five seconds and made no sound. Bugling is an entirely different posture. When a bull bugles, his mouth is rounded and the upper lip is not pulled back. The little clump on his left brow tine is dirt and grass which remained after he scraped his antlers across the grass. The elk mating season or rut occurs in September. Their high-pitched whistle or “bugle” is a surprising sound coming from such a large animal. The bugling is a challenging or defiant call to other bulls, telling them – “I am here, I am strong, I am in charge.” Bugling actually includes a variety of calls: grunts, popping sounds, whistling, and deep moans. Male elk urinate on the ground, roll in the dirt and mud, rake their antlers across the ground and through grass and small trees, using up much of their energy for more than a month. Thus the most aggressive bulls lose a lot of sleep and weight. If there is an early, hard winter, these bulls will be some of the first to winter kill. It seems counterproductive for them to be among those most likely to die; but, these strong bulls should have many of their genes successfully living on in the upcoming spring crop of calves.