It is 7:00 AM and the “Bison of Yellowstone” course is due to begin in a couple of hours. There are a few of us mingling around the bunkhouse, enjoying our morning cup of joe. As I look down the pathway to the cabins, I cannot believe what I am seeing.
I call over the students as I open the bunkhouse door. A gorgeous bull bison, sporting a full beard, pompadour, and swaying pantaloons, is meandering down the walkway, heading for the bunkhouse. His timing couldn’t be better! He walks across the front porch and down the side of the building to the foot of the stairs at the back porch. His behavior electrifies us as he grunts and snorts, then proceeds to urinate. We believe he is agitated with us, as he trots off to the corner of the ranger residence next door. He exhibits the same behavior there, then drops down, rolling in his urine. As we look across Rose Creek, which runs through the ranch, another magnificent bull and the cow he is tending are watching, and this show is all part of the bull dominance so often displayed this time of year. Welcome to the rut!
Beginning mid-July and continuing into the early days of September, the bison rut is on in Yellowstone. Bulls do most of their communicating during this time of year, their breeding season. Often during the rut the bulls could be heard from our cabins, snorts and bellows sounding more like a pride of lions. It was eerie and exhilarating.
During the rut bull bison focus their attention on the cows, trying to determine when they enter estrus, the time when they are receptive to breeding and can be impregnated. A cow’s urine is full of information on when she is nearing ovulation. The bull has a vomeronasal organ in the roof of his mouth than can analyze female urine and determine if she is receptive. Sticking his nose into the cow’s urine, he raises his head with upper lip curled, tongue reacting as if he is tasting a fine wine. This action, called the flehmen response, is common in most ungulates. We observed this behavior during our time in the field, after which the bull chased the female, a sure sign he felt she was ready.
So what does all this bull posturing mean during the rut? Here are some of the questions that I had answered:
Q: What does that raised tail mean?
A: It could mean one of two things – charge or discharge. When a bull or even a cow is agitated, they lift their tail into what looks like a question mark. A raised tail is often seen on the bulls during the rut, as their testosterone levels keep them agitated much of the time. As for the discharge, do I really need to explain that?
Q: What’s all that rolling around in the dusty wallows about?
A: All bulls wallow several times per day during the summer, probably ridding themselves of insects and perhaps reducing their body temperature. No one knows for certain why a bull urinates into a wallow before rolling in it during the rut. Perhaps he is showing his male dominance to other bulls, or is he trying to impress the gals?
Q: How does a bull choose a female?
A: Sorry guys, but the girl has the final say on who sires her calf. The bull expends a lot of energy trying to “tend” a cow when he knows she is nearing estrus, but the cow is looking for a high-ranking bull, one who has been tested through a few winters, battles, predators, etc. If she doesn’t think the guy lavishing her with attention is going to be a fit partner, she will take to running, prompting other bulls to chase her. Who she ends up with may not be who she came to the party with.
Q: Are bulls monogamous?
A: Seriously, not even close. Bulls are quite the cad, trying to impregnate as many cows as they can during the rut, in order to extend their lineage. And if that wasn’t bad enough, they can’t be said to be good fathers either. After the rut bulls can be found alone, enjoying the warm sun, eating and ruminating, resting and preparing for the winter. But I still love you guys!
Q: Now to the touchy subject of bison sex. I don’t want to sound like a voyeur, but how does all that work?
A: Don’t blink or you might miss it! Bison sex takes a whole 4-5 seconds, with the bull putting his front legs over the flank of the female. At the time of ejaculation, the force of his abdominal contraction is so strong that the bull is literally lifted off the ground, placing all 2,000 pounds of him on the cow’s back. It’s no wonder that a cow can be seen limping for days afterwards. It begs the question, can you blame a girl for not being that interested in sex?
Q: How often during the rut do bulls fight, as in head-to-head combat, like we so often hear about?
A: Surprisingly, bulls try not to fight with other bulls if possible. They lose, on average, 200 pounds during the rut as they turn their attention to tending cows and having sex instead of eating. Winter rapidly approaches after the rut, and they need as much energy as possible, stored as body fat, to help get them through the cold, harsh days. Time spent fighting means time taken away from breeding and valuable energy expended. Bulls try to modify another bull’s behavior instead, getting them to submit. This is where all the posturing; e.g. grunts, bellows, rolling in wallows, stamping of hooves and shaking of pantaloons comes in. The winners of this posturing don’t spare their rivals, rather themselves. Some ecologists believe that it is typically the older bulls who are more likely to engage in battle to win the girl, as they have less to lose. “An old bull is a bold bull”.
Because we have so much more to learn about these majestic creatures, doesn’t it make sense to preserve some wild spaces for studying them and other wildlife?
~ The Ends ~
If you are interested in learning more about the educational programs offered by Yellowstone Forever, go to www.yellowstone.org and check them out. You won’t be disappointed.
Disclaimer: The views expressed here are my own and do not necessarily represent the views of Yellowstone Forever.
42 thoughts on “The Bison of Yellowstone ~ Yellowstone Forever Field Seminar Series, Part 2”
What an exciting experience for you and the students!! The bull was definitely not happy with you peaking out for that photos:) I love these big furry bison. Thanks for sharing all this information…things I didn’t know:)
It was the perfect beginning to the bison class. Glad I could educate you a bit Pam. 🙂
Just great teacher. Thanks for the lesson.Didn’t know all that. Frank
Always aim to please Frank. 🙂
Fantastic experience and interesting post. Great photos of these strange and imposing creatures….they are amazing.
Thanks Jane, and yes, they are amazing!
Interesting! Probably more info than I needed! I saw the Elk during their rut (buguling) in early October! They take over Estes Park and the golf course! Animal behavior!! 😊
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Gotta love it! 🙂
Great lesson on bison. It was funny and interesting! You sure learned alot. Did you name those big boys.Margee
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I didn’t name them but I truly grew to love them.
I have already learned more than I knew, before reading your blog, today. What are some of the books you have been reading, about these great characters? As always, I love the pictures you have included, with this story. Patiently(?) awaiting your next chapter.
I think the best book I could suggest would be the American Bison book by Dale Lott. He grew up on the National Bison Range in MT.
Thanks for the nature lesson on bison! Loved the ‘read’ on their behavior, LuAnn.
Beautiful Bison photos and one of them even posed for you! Great Bison lessons, thanks Luann, quite interesting and fascinating. I think you have the best summer of all!
Fabulous photos! Thanks for this interesting bison lesson.
My pleasure. Hope you had a lovely summer!
They are really magnificent creatures.
They certainly are!
Thanks for all of that information about the bisons and your excellent photos. So many things I didn’t know!
Me neither until I took the class.
Oh my what an astounding experience LuAnn. I’ve learned a great deal from your article. Amazing photos of the action.
I love those big guys!
Fabulous post LuAnn, and wonderful photos. It must have been amazing to see so many bison up close.
Yes it was!
Lu, this was SO much fun to read! I learned a lot, and you kept me interested in a topic that I didn’t even know I was interested in. You’re a very good teacher. 🙂 Were you always interested in bison, or did your interest begin with your summer in Yellowstone?
That is exactly what happened to me this summer Laurel. I supported classes that I wasn’t sure I was even interested in and was pleasantly surprised by how much I enjoyed each one of them. I have always been drawn to bison but really fell in love with them after doing some reading and then supporting the bison class during the rut. They are fascinating creatures to watch, especially when they are just a few feet from your front door.
What a cool summer you’ve had…and SO many things I did not know at all about Bison!
It was a summer of learning. It looks like you two have had a great summer as well Nina.
Oh LuAnn, I just loved this post. As I read it, I couldn’t believe what I was reading. About every few seconds I would say to Paul….listen to this….listen to this….did you know this. At one point, he said, “Marsha, how the heck do I know anything about Bison sex?” I just laughed and said, “Sometimes you act like you know everything.” He didn’t laugh…hehe
What an amazing class. I will never look at a Bison the same way again. The poor cows. Walking with a limp is probable the least of her worries. Thanks for such a cool post. I truly enjoyed it.
It is nice to find someone who seems to enjoy bison as much as me. I always loved seeing them but after taking the class and reading a few books, I am so enamored. They are amazing creatures. I loved reading this comment Marsha. 🙂
Thank you, LuAnn! Love your writing and enjoyed the q&a format! I just love these animals. They are part of the best of the USA, and they represent us as a nation: back in the late 1800’s. LONB before any Endangered Species Act, we as a nation worked to save these bison from extinction. Special creatures on all levels.
Thanks Julianne. The bison indeed are part of the best of the US, as is Yellowstone. 🙂
Seriously? Literally lifted off the ground? I can’t help but laugh. I am guessing with only a 4-5 second window, timing was not in favor of a Kodak moment…or are you just keeping to a PG rating? LOL!
I unfortunately am not that quick to take such a photo but I did have a glimpse in one of the books I read. I feel sorry for the poor female. 😦
Fantastic photos! What a great post, thank you so much!
My pleasure! Thanks for stopping by!
Absolutely fascinating LuAnn! That must have been quite a site to see outside the door of your cabin window. Did you primary study bison or did you also study other animals? How many babies are born during the rut season? I can’t imagine being there. How magical!
It was so fascinating to see entire herds of bison wander through the ranch. During the rut we marveled at how it sounded like a pride of lions was right outside our door. I surrounded a bison class and a wolf class this past summer, along with wildflower classes, a Native American class, geology and thermal biology classes, as well as a sketching class and a hiking class. It was amazing! I don’t know how many babies are born during the rut. Since there are upwards of 5,000 bison in the park now, I’m not sure anyone is tracking how many are born during this time.
Wow what a spectacular summer. It must have been so incredible for the heart and soul.
Yes it was!
Thank you so much for this wonderful post with so much interesting information and wonderful photography❣️Amazing animals. 😊
My Pleasure Dina!