Yellowstone NP in September: A Good Time To See Bison And Experience The Rut Without Crowds
On a September trip to Yellowstone National Park, I became a tad obsessed with the American bison, the national mammal of the U.S. The weather was perfect (blue skies and in the seventies most days) and the crowds were low (although parking was still challenging at key geyser and hot springs areas).
We were there for the tale-end of the rut which, in my mind, is the best time to experience bison. They are magnificent beasts that we enjoyed watching for hours across several days.
Since prehistoric times, Yellowstone—the only place in the lower 48—has been home to a free-ranging bison population. And, although the population dwindled to near extinction in the 1800s, today the National Park Service preserves a sustainable population of 3,500-6,000 wild, migratory bison.
These animals deal with brutal winters, predators (wolves and bears), and ‘tourons’ (tourists that are morons), and yet, they don’t just survive—they thrive.
Where You’ll Find Bison
Bison are found in many areas of Yellowstone. You’ll find older bulls off on their own in fields, near rivers and hot springs, and even roaming parking lots. Herds of bison on the other hand, are found mainly in Hayden Valley and Lamar Valley, where they roam freely. These valleys are particularly large so some herds will be off in the distance, quite a ways from the road. That said, if you cross the valleys a few times during your Yellowstone visit, you’ll invariably experience small herds of 10 or 20 animals crossing the road in front of your car or a few cars ahead of you.
“On several trips through the valleys, bison were so close to our car we could practically count their nose hairs and smell their fetid breath.”
What You Should Know About Bison
They’re wild animals—unlike family pets—and can be aggressive and unpredictable.
They’re huge—think in tons not pounds. Males (bulls) weigh up to 2,000 pounds; females (cows) weigh up to 1,000 pounds.
Due to their size and stance as they graze, they may appear slow-moving, but they’re way faster than any human on foot (they can run up to 30 miles per hour). And, they can jump a 5 foot fence from a standing position with ease—I saw this near Old Faithful Inn—so don’t think a wire fence between you and a bison means protection.
Bison live, on average, 12–15 years and feed on grasses and sedges; their muscular shoulder bump enables their heads to move from side to side easily when they need to plow through snow.
The mating season (a.k.a. ‘the rut’) is in late July through September; cows give birth to one calf in late April or May.
Bulls vs. Cows
Bison bull (back) and cow (front). (Photo: Erik Kramer)
Most times, bulls are easily recognizable in a herd because of their massive size—sometimes double that of a cow. Bulls are taller and bulkier than cows, especially in the head, shoulders, and neck, and their shaggy, long beard and mane is a quick differentiator.
In addition to physical differences, a bull’s demeanor tends to be more restless than a cow’s—bulls bellow and paw the ground, and seem a bit grumpy or standoffish during the rut. Some bulls we saw at Yellowstone were less distinguishable from cows, probably because they were adolescents and, although quite large, had not developed all the classic features of a mature bull.
The Rut
A bison herd will differ during and after the rut (the mating season).
During the rut (July-September), bison form a herd that includes bulls, cows, and offspring.
Bulls become more aggressive and competitive, bellowing and engaging in displays of strength to establish dominance and earn the right to mate with prized females. As bulls mature, their experience level and dominance status increases as does the strength and energy they require.
It’s tough at the top, and that’s no bull!
After the rut, cows and offspring form large matriarchal herds. Bulls, including young males ready to leave the matriarchal herd (starting around age three), form small bachelor groups. The two groups separate for the majority of the year.
Bulls rest, recover, and the oldest retire. Cows go through pregnancies, deliver calves, and watch over the offspring through most of the year without a mature bull in their herd.
Herd Mentality
Bison grazing near the main road in Yellowstone’s Lamar Valley. (Video: Edie Kramer)
Individual bison show unique traits including some that are characteristic of their respective maturity levels. You can also observe the herd’s hierarchy in action, particularly during the rut when all members are together.
Yearlings (calves) are obvious because of their size and energy level. During their first few months, calves are orangy-red in color (hence why their nickname is ‘Red Dogs’). They stick close to their moms (we saw several nursing in September), and are quite playful. Just like your pet dog, they can get ‘the zoomies’ without notice—you’ll see them running, kicking, and butting heads with each other while the rest of the herd pays little attention to their antics.
Females (cows) begin breeding at the age of two and only have one baby at a time. They are the workhorses of the herd. They deal with pregnancy during the tough winter months, give birth in the spring, take care of the calves, and raise male juveniles through their first 2-3 years of life without mature male support.
Mature males (bulls) are in their prime for breeding between age six to 10 years. As mentioned, bulls are aggressive and competitive. It’s all about establishing dominance.
When you watch a herd during the rut, it’s clear who the top bulls are and even which females are prized by one or more bulls. Youtube has videos showing bulls running and hurling their competing males 10 feet or more. That’s 2,000 pounds flying through the air during a scuffle. And this type of aggression happens very quickly. No wonder they rest and recover outside of the rut.
“It’s tough at the top, but there are a few perks too.”
But these primo bulls have some impressive perks for all their bellowing and bluster during the rut.
First, they get the prized females when they feel the itch.
Second, they pick fights with the competition to show off their male hood (bull hood?) a bit.
Third, they shove off for a good chunk of the year to hang out with their buddies (shirking all calve-rearing duties). And, they leave the cows after the rut to deal with pregnancy, birth, and the kiddos for the bulk of the year.
Fourth, there are no hard feelings on the part of the ladies. They’re welcomed back the following rut season to repeat the cycle.
I can hear some men (and some women too) saying, ‘Sign me up!’
Bison bull stops traffic while herd crosses the road safely in Yellowstone’s Lamar Valley. (Photo: Erik Kramer)
Bulls are in charge. As an example, when a herd is about to cross the road, one of the largest bulls in the group will literally block car movement by standing in the middle of the road so neither side can pass. Another bull of nearly equal size might follow suit to assist him. Then, all the cows, calves, and younger males cross the road. Once every animal in the group has crossed safely, the bull will move on. The bull also seems to determine where the herd is going as they graze. On several occasions, we saw herds following the bulls when they criss-crossed the valley.
Old Bulls wander away from the herd, preferring a more quiet lifestyle. They’re ready to retire from the aggressive rituals that the annual rut brings. And they know there are younger and stronger males that they can no longer compete against. According to one park ranger I spoke with, bulls come to a point in their lives when they prefer to be left alone. Just like a lot of old men!
Retired bulls are often seen in busy areas of Yellowstone. (Photo: Erik Kramer)
We were watching a lone bull in the busy Old Faithful Inn area, grazing near a parking lot. The park ranger, who was positioned there to maintain distance between the bull and visitors, said that because of their size and strength, predators tend to leave retired bulls alone, targeting the large herds of more vulnerable cows and calves in the matriarchal herds instead. For added safety though, you will find retired bulls hanging around some of Yellowstone’s busier areas where people are (and predators shy away from).
Why The Hump?
The hump allows bison to swing their heads from side-to-side and clear snow as they forage for food during the long winters. (Photo: Erik Kramer)
Both male and female bison have a shoulder hump—you can’t help but notice it. Their heads dip low to the ground as compared to other mammals. The hump is actually a large neck plus strong shoulder muscles. The combination allows them to swing their heads from side-to-side and clear snow as they forage for food during the long Wyoming winters. Snow in Yellowstone can arrive mid-October and reach an average of 150 inches a year. It’s not uncommon for higher elevations to get twice that amount. The hump is essential to their survival.
Close Encounters
Close encounters with bison (within 20 feet) should be done from the safety of inside your car. In Yellowstone, you’ll see tourons (tourists that are morons) who lack all common sense and respect for these animals, standing within 10 feet from these beasts with their cameras and tripods at the ready.
When rangers are telling people they are too close and that these animals are wild and can be unpredictable, I guess these tourons think the message is for everyone else. ‘Cause they’re special. And they only need one more minute for that selfie. Rangers have the patience of saints.
I saw one person roll down their window to try and pat a bison as it passed the passenger side of their car. Moronic behavior that could have sent them to the E.R. I’ve no idea how the overworked park staff is able to maintain a calm demeanor when dealing with these idiots.
When you visit Yellowstone, or any U.S. National Park, don’t be a touron!!
