What to know about the fastest animal in Colorado
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GRAND JUNCTION, Colo. — The pronghorn is the fastest land mammal in North America, comfortably matching the pace of a car at highway speed. But what else is there to learn about the striking ungulate — large mammals with hooves — that is at home in both the desert and the mountains?
Rocky Mountain PBS recently spoke with Colorado Parks and Wildlife biologist Lace Carpenter to learn more about pronghorn in our state.
Carpenter is the senior wildlife biologist in CPW’s northeast region, managing big game and non-game animals from the Wyoming border, down the Continental Divide and out to the Kansas border. The CPW regions roughly divide the state into a foursquare field, with some jagged edges around Lake and Park counties.
The following interview has been edited for length and clarity.
Rocky Mountain PBS: Let’s get right into it: Are they pronghorn or antelope?
Lance Carpenter: They are pronghorn. Antelope are old world, it's kind of a mistake to call pronghorn antelope. They belong to their own family here. The old world antelope are in places like Africa.
They're one of the coolest animals that we have, I think, on the plains right now. They are the fastest North American animal. They are actually just spectacular animals to watch.
RMPBS: What do they eat?
LC: Grasses, forbs [broadleaf plants that are not grass-like] and browse. In the eastern plains we have short grass prairies, for example. They'll eat the leaves off a tree or shrubs, that's what we call browse.
RMPBS: Where in Colorado do they live? What kind of climate or weather can they live in?
LC: Eastern plains, east of I-25 to the short grass prairies. We also have pronghorn in some of our mountain parks like South Park, North Park, and Middle Park. Over on the Western Slope, the Book Cliffs. We have them in the San Luis Valley. They're pretty widespread in Colorado.
They're variable. There's pronghorn up in Wyoming and Montana, you know, on the eastern plains there. In the desert, they're over in Utah as well, like the Great Basin Desert, for example. They can handle a lot of different weather.
RMPBS: Is there a noticeable difference between the males and females?
LC: The males, or bucks, always have a black patch on their cheek. So, if you’re driving along and see something black on their cheek, that’s a buck.
Usually, the does have one fawn, but sometimes they can actually have twins. What's really cool about pronghorn is when they drop their fawns, the females will be in the herd, but then when they give birth, they actually kind of go away by themselves.
For the first couple of weeks that it’s alive, the fawns actually have no scent. The natural predators can't find them. So, what happens is the doe will go drop the fawn, she will stay around that fawn, but not near it. She'll come in, nurse it and then leave. She's not far from the fawn, but because the fawn doesn't have a scent it's hard for predators to find.
That's why the mom kind of stays away from that newborn fawn. But she's always kind of close by. It's not like she takes off and goes miles and miles away.
Their horns are actually like your fingernail, the material your fingernail is made out of, that's the same thing that they're horns are made of. There's a core that is bone, and on top of that, it's just a sheath [of keratin].
And one of the reasons they call them pronghorn is because on the sheath they have prongs that stick out. If you look at one really close, you'll see that.
RMPBS: What do you do as far as research or wildlife management specifically? What's your interaction with pronghorn?
LC: Since they're a big game species, we do classification flights. We're actually flying and we see pronghorn on the ground. We'll classify them, it'll be like “doe, doe, buck, fawn, buck,” and that kind of gives us an idea of what productivity is like.
Especially, you know, because drought can impact pronghorn. If there's a lot of drought, which we've actually seen in the northeast, the survival for the fawns is really poor. It can really impact what we call our fawn-doe ratio, how many fawns we see compared to how many does we see.
There's a lot of work that goes into figuring out an estimate of how many pronghorn that we actually have. We have the different herds that make up what's called a data analysis unit.
And within that, that's how we kind of manage that herd. Like we have a population number that we're shooting for, some range, I'm just making this number up, 1,000 to 2,000 pronghorn. That's how many pronghorn we want in that particular herd. If we have too many or too few, we adjust [hunting] licenses to make sure we keep the population in the objective ranges for that herd.
RMPBS: What diseases or predators do they face?
LC: We don't really have chronic wasting disease with pronghorn. That's more often in deer.
Mountain lions, coyotes — if they can get the fawns, they will definitely prey on them.
It might sound really bizarre, but golden eagles. Golden eagles can take fawns. That's probably rare, but we actually had one in Utah that was taken, killed, by a golden eagle. We actually saw it, which is the craziest thing. I mean, I was blown away by that.
RMPBS: How far do they travel? How far does the herd move within an area?
LC: It's highly variable. It's very dependent on food. In [one management area] for example, we actually have pronghorn going up into Wyoming. So, we have Wyoming pronghorn coming into [Colorado] and vice versa.
A home range can get from 165 hectares to more than 2300 hectares [over eight square miles]. Summer ranges are typically bigger than their winter ranges. And in the winter they kind of contract, at least here in the northeastern part of Colorado in the winter time, they spend a lot of time in the agricultural fields. When we have big snows, they’ll go in those ag fields.
RMPBS: What else do you do in your work with pronghorn?
LC: We're actually just starting a very cool pronghorn study here in the Northeast region. This herd is in a general area from Fort Collins to Wyoming all the way out to Julesburg, and that area is called PH1.
We put 120 to 140 collars on those pronghorn. We distribute them across that herd. And what we want to look at is where they're moving in the wintertime, what habitat they use. Are they in short grass prairie? Are they on ag fields?
With the collars that we have on, we're going to be developing a habitat model. Based on all the data, we can say “this is the kind of habitat the pronghorn like in the wintertime. This is the kind of habitat that they like in the spring or summertime.”
And that will help us because obviously in the northeast region, we have a lot of energy development here both oil and gas and renewable energy. It will help in determining where some of those places can be, especially for our renewable energy like solar. It's going to take us a couple of years to get that data. But once we do it’ll really help out and be able to have that middle ground between having our wildlife and renewable energy, so the renewable energy doesn’t impact some of our pronghorn as much.