23 April 2025: Grouse Lek Extravaganza with She Flew Birding Tours.
Day 5: Dusky grouse lek, Sharp-tailed grouse lek, Walden Reservoir, Arapaho NWR, to Walden
Today in addition to seeing two species of leks we will encounter pronghorn (Antilocapra americana), the fastest land animal in North America and the second fastest land animal on Earth. I hope to see them run!
In Pennsylvania we’re quite familiar with white-tailed deer so let’s compare the two.
Pronghorns are the same shoulder height as white-tailed deer but they weigh a lot less. When fleeing danger both show white rumps/tails, but when it comes to running pronghorns are really really fast. This table shows the biggest differences between the two.
| Traits | Pronghorn | compare to deer | White-tailed Deer |
|---|---|---|---|
| Speed | 55-60 mph in 0.5 mi 35 mph for 4 miles | TWICE as fast | 30 mph in short bursts |
| Average weight of male | 60-70 pounds | HALF the weight | 140 pounds |
| Height of jump | gets stuck at fences | CANNOT jump | 7-8 feet high from a standstill |
55-60 miles per hour sustained for half a mile!
But they can’t jump, so fences shut them in. That’s why they are running on the road below. (The narrator mistakenly calls them deer.)
Why do pronghorn run so fast? This 10 minute video is a Deep Dive into paleolithic history and the predator that lived in North America that prompted them to run. If you don’t have 10 minutes, watch the first part.
p.s. And by the way, their closest relatives are giraffes and okapi, not antelopes.