DENVER — After news that two wolves reintroduced in Colorado have reproduced, 9NEWS spoke with Brenna Cassidy, Colorado Parks and Wildlife's wolf monitoring and data coordinator.
(This conversation has been edited for clarity.)
What is a wolf den?
Dens can be really variable. A den can be a hole in the ground, or it can be just a depression under a log or a rock, or, you know, under some sort of cover.
What we classically think of with a den, though, is a hole that's dug out by a female wolf. Whether it's something that she digs new or that she digs out like an old coyote den or badger den or something like that, and it's a hole in the ground that generally has a little bit of an entrance and then kind of a tavern, or so, that has enough space for her to go in lay down, stand up, turn around. And that's where the pups are born and where they'll spend the the first couple weeks of their life.
What is a wolf's gestation period?
Wolves generally breed in mid-February or so, and then their gestation is very similar to a dog. It's a little over 60 days. So that means that they'll give birth in mid-April.
These two wolves met and bred sometime this winter?
Wolves only breed once a year, unlike dogs, so they must have met at some time before mid-February, bred in mid-February, and we think that she probably gave birth sometime in mid-April.
How did you confirm there is a pup, and how many are there?
We know of one. There could be more. This week was just the first time that we saw a pup.
We have had the idea that the mother has denned since about mid-April. When a female goes underground into a den, her GPS collar can't communicate as well to the satellite, so she'll start missing a couple points, or a couple uploads. When those are missed, we think that maybe something is going on, that she might be underground and not able to communicate with the satellites.
Then when we do get those points when she is outside the den and they upload, they'll all be localized in one spot, and she might go and get a drink of water or she might come outside the den and stretch or something. But they are very localized in one spot for days or weeks at that point.
What was it like to confirm your suspicions were correct?
It's a really, really exciting feeling to know that there's a pup out there after this first year of translocations of wolves in Colorado. It's really exciting.
Even though all of this female's behavior indicated that there was a den there and that we had some sort of reproduction, being able to see a pup and know that it's out there is really exciting.
How were you able to see the wolf pup?
This is just our routine monitoring.
Routine monitoring includes things like trying to get observations from the air, trying to get observations from the ground, from an observation point, putting out trail cameras, even looking at public sightings reports.
There's so many people out there that's really useful to have that many more eyes out there, so this is just standard monitoring for us.
Are there are photos of the pup?
We don't have a photo at this point. We have trail cameras. We're going to leave them out there just to have them collect as much data as possible. And I I hope we get photos.
How is the wolf pack's name determined?
Packs will all be named after geographic features in their territory. So the Copper Creek Pack, Copper Creek is is a feature in their territory.
We're not naming packs after people names or other animal names. This was a nice name that kind of had a geographic meaning that wasn't a human or animal name.
If one, or both, of the pups parents have eaten cattle, would they be expected to pass that behavior on to a pup?
Generally in the Rockies, wolves will preferentially choose elk, and that's over deer, that's over moose. That's over livestock. Wolves are generalists, though. If they happen upon something besides an elk, they may hunt it and kill it.
These adult wolves have eaten natural prey in the Copper Creek pack. They're not just subsisting off of livestock. These pups won't be copies of their parents. Even if an adult wolf has killed livestock before, that doesn't necessarily mean that pups will do the same thing.
There's also a possibility that with a larger pack, it will become easier for that pack to hunt elk because even one wolf or two wolves, they can hunt adult elk. When we get into next winter and next spring when these pups grow up – assuming there's more than one – when these pups grow up and are able to be helpful hunting, the optimal group size for hunting elk is four. So if they could get to that number, that would be good news.
Does the female wolf stay at the den and the male hunts?
Early on, when the pups are nursing, the female is sticking around that area a good bit. She just can't go super far because the pups need to eat, you know, at a decently high rate.
After those pups are weaned, when she's able to join him, they might go out together and hunt. They might go out separately and hunt. It's during this time, when they are hunting mostly elk calves or deer fawns, there doesn't necessarily need to be two of them to do that, so they could be on their own, but each of the adults going out on their own.
What are we not asking?
It is interesting with this pack, with it just being the two adults. Often when when there are more than the two adults, the other – whether they're older siblings or aunts and uncles of the pups or something , they'll be doing very similar things to the adults, will be going out and hunting.
They will be going and feeding the pups from whatever they went out and brought back. The wolf pack centers around pups. It is extremely important to them. All the wolves in the pack gather around to help raise these young animals, which is pretty impressive for these social animals.
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