First up was Bob Huddelson, the owner of Lost River Game Farm, and apparently a breeder of such animals. His response was rather bemused:
This almost sounds like a joke. A red fox makes about three different noises, but I’m not about to make them on the phone right now. You know how a cat purrs? Ok, when a fox — when a female fox — is looking for a male fox she does a loud purr that is very loud. And she’ll make that, and it probably lasts 3 seconds or 4 seconds. That’s one noise that a fox makes. Then, if you stumble on a fox’s den where she’s got puppies and she feels like you’re a threat, she’s got a wild scream that she makes that 99 percent of people would run for their lives [from], and that’s the idea. When that happens, she’ll move the puppies to a new den. A young fox, they make two or three noises as well. Most of them are soft, kind. [Sounding slightly exasperated] You have to play with a young fox to really hear what they’re like.
For comparitive purposes, HuffPost then obtained a response from Brian L. Cypher, a research ecologist at California State University studying San Joaquin kit foxes:
I’m actually away on vacation and just saw this. Probably too late to do much good. And anyway, most of my work has been with kit foxes and island foxes. They are relatively quiet compared to other foxes. I’m assuming the fox in the video is likely a red fox, although I haven’t see the video yet. Red’s tend to be a bit more vocal, from what I understand.
And then, I found this video of a screaming red fox:
So, that’s settled then. Foxes make several noises. And judging by Bob Huddelson’s decription and the red fox screaming video, Ylvis wasn’t that far off after all…