Otter or Beaver?

The other two mammals commonly mistaken for otters are primarily vegetarians.

The beaver pictured above is building up its dam. something you'll never see an otter do. Otters fish around beaver dams, sometime scat on top of them, and sometime dig into them, but they don't carry sticks to a dam. Sometimes they carry clumps of vegetation when they are trying to make a more comfortable place to lie on top of a beaver's lodge. On average beavers and otters are about the same length, but on average the beaver is many pounds heavier: 30 to 70 pounds for adult beavers and 12 to 20 pounds for the adult otter. In the photos below the otter looks heavier but that's because it swims more out of the water, because it is lighter!

Here's a video of a beaver bullying an otter out of its pond. You can see the stolid style of the beaver and the quicksilver style of the otter -- more like a fish.

But its hard for the beaver to hide its big triangle shaped head, bigger ears, and notice that paddle shaped tail, quite unlike an otter's tail shown close-up below.

Over the years I've often initially mistaken beavers for otters, especially when the beavers are diving for roots at the bottom of a pond, for otters. The photo shows the base of a diving beaver's tail.

But in a few moments when the animal came back up to the surface, I saw the beaver's big head and ears and noticed how slow it was. Still, in the evening it can be tricky. Otters dive in the water and often eat the fish they catch by clutching it in their paws while they eat it. Beavers don't just east trees. They dive in ponds and bring up vegetation, soft grasses and such, hold it in their paws and eat it up with their head. But as you'll see in the video below, when they dive you just see the base of the tail, and the head is shaped differently.

On rare occasions an otter will lolligag out in the water floating like a log which is what beavers often do. And beavers can surprise you with their agility in the water, especially if you scare them at the edge of the pond. I did that to a yearling beaver and it swam so fast underwater that it made an impressive wave and wake in the shallow pond.

When a beaver tires of your presence, it often makes a big splash with its tail to try to persuade you to leave it alone.

Otters have a different style. Remember those otters that swam back to get the tailless bullhead that I was so rudely standing over? Their heads soon popped up and they gruffly snorted at me, a noise they make by blowing air through loose lips. Otters don't chatter as much as they do in the sound tracks of the nature films like "Yellowstone Otters." Remember, almost all sound tracks are spliced in later and juiced up to add to the visual excitement. I can watch a group of four otters fishing in a pond for an hour and never hear any noise save the occasional splashing of water.