Here’s a short video from UC Santa Cruz that lets you listen to some of the weirdest calls in nature. Elephant seals look like living sand dunes and sound like water in backed-up sewer pipes. Their sounds may be more individualized than we previously thought.
I’ve been out to visit elephant seals a couple of times in my life. One of those times I spent several minutes listening to a male elephant seal call out before I realized that that was what I was hearing. To me, it sounded like bubbling water pipes. I thought something was wrong with a drainage channel nearby. As you can hear in the video, that’s a reasonable mistake to make, for a human.
Elephant seals, apparently, are a lot better at assessing the sound. The males can recognize other males’ voices. If the voice comes from a male bigger than them, they retreat. If it comes from a male smaller than them, they go after it.
(Incidentally, I love the moment at 1:17, when the male is clearly fed up with a nosy biologist recording him and starts to chase the guy. I wish they’d shown what happened next.)