What’s Wildlife Up To This Fall?


In an ecosystem with the dramatic seasonal temperature swings of Grand Teton and Yellowstone National Parks, the landscape and wildlife can look remarkably different from month to month. If you have only visited the parks in one season, returning to visit another time of year will reveal a whole new world of wildlife activity. Here is a calendar featuring some of the wildlife highlights from month-to-month across the Greater Yellowstone Ecosystem this Fall.


If you would like to see a pronghorn reach a speed of over 50 miles per hour, September is the best time of year to observe these elite athletes show off their skills. Males accompany small groups of females and are kept busy not only chasing off rival males, but also trying to keep the females together. When they return to their harem after escorting a rival miles away, we can often observe the black tongue as they pant – a trait they share with their closest living relative, the giraffe.


By early October, the golden leaves of aspen are at their peak and so is the rut of the Rocky Mountain Elk, or Wapiti. The mountains echo with the bugles of the males, a behavior that intimidates other males and impressed the females. A successful male could lose up to 25% of his body weight as he is run ragged breeding with his harem of females and chasing rivals.  Satellite bulls – younger or less impressive bulls – stalk the edges of the harem, always alert for a moment of distraction from the large bull. The first bugles of the rut can be heard as early as late August, but the peak of the breeding season runs from mid-September through mid-October.


November is the month of transition from fall to winter and is the best time of year to observe and photograph bull moose. While their breeding season parallels the elk in September and October, they are actually more readily visible in November and December as temperatures cool down and cloudy weather increases. Dozens of moose emerge in Grand Teton National Park to feed in areas with high concentrations of Antelope Bitterbrush, a high-protein shrub that the deep snows of winter and the high temperatures of summer prevent them from accessing at other times of year. Bull moose retain their antlers through November in hopes of perhaps attracting a female that is late into estrus, but as winter hits hard in December, the antlers become a burden and begin to shed. By February, it is unusual to see a bull moose with antlers until they begin to regrow in May.

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This post was guest written by Wildlife Expeditions guide, Sarah Ernst. Sarah is a passionate educator that has been guiding for Wildlife Expeditions since 2011. She loves using stories, science, and dialogue to help her guests learn, connect, and form a deeper relationship with the national parks as well as their own home ecosystem. She received her Bachelor of Arts in Philosophy from Mount Holyoke College in South Hadley, MA in 2005. Prior to arriving in Jackson Hole, Sarah was the Education and Exhibits Coordinator at Kiawah Island Nature Center in South Carolina. In her free time Sarah enjoys exploring the Greater Yellowstone Ecosystem with hiking boots, kayaks, skis, and snowshoes – usually accompanied by her loyal dog Linus.


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