The first time I heard this sound in the dark, I had no idea what it was.
For those of you who don’t live where there are raccoons, I can tell you they are much more dog-like than you’d expect from animal that isn’t actually canid species. When you look into the eyes of a raccoon, it’s like looking into the eyes of a dog. This is a creature with a mind.
Probably the best way I can describe them to those who have never seen one in the flesh is they are kind of like a dog mixed with a primate and a bit of bear thrown in for good measure.
And when they are scared, they make lots of strange noises, including this alarm bark that sounds a bit extraterrestrial.
I did, in fact, know that raccoons bark. They also make a rattling sound that sounds much like a loud purr (but isn’t).
They DO make strange sounds. I watch a den in a huge retaining wall in NYC’s Riverside Park. Pretty much every year there are babies, and often multiple generations living in there. One year, I heard an extraordinary array of sounds coming from the mouth of den. I figured it was fed-up Mom reading the riot act to the adolescents inside. There was barking, growling, snarling, chittering, and more. Sounded like a brawl, but no one seemed any the worse for wear when I saw them again.
It’s like a dog bark mixed with a horse’s neigh.