Watching a Hunting River Otter

River Otter swimming at the water surface.

I was driving along the Dolores River the other day.  The river was shallower than usual for this time of year, and there were still patches of water that were iced over.

I happened to notice a wake on the surface of the river below, and stopped to see what was causing it. I figured I’d see some Mergansers.

Wow. My jaw dropped - the wake was caused by a River Otter. I got out of the Jeep to get a better view.

The Otter was hunting - it was swimming along the surface until it saw something interesting, then would dive down. About half the time it would dive, it would return to the surface with something in its hands or mouth.

River Otter manipulating a captured Crayfish before chomping it on down.

The Otter would spend a minute or so manipulating whatever it was catching, then resume hunting. When I zoomed in on one of the photos I’d just taken, I saw that the Otter was catching Crayfish.

The Otter and a captured Crayfish eye each other.

There was about a 10 yard drop from the road down to River, and I was about 150 yards away from the Otter. I probably could have gotten closer, but didn’t want to try to get closer lest I disturbed the Otter.

As it worked out, though, my position above the river allowed me to look down into the water and see the Otter hunting underwater.

The Otter’s dives - its tail and hind feet skim just below the surface of the river as the Otter’s head skims above the rocks of the river’s bottom.

The Otter has captured a Crayfish and has rolled over on its back. The Otter is holding the Crayfish in its hands and is getting ready to eat the Crayfish.

Watching the Otter hunt was a spectacular experience. The Otter was so agile, so flexible. It seemed to move through the water with no effort whatsoever.

There was also a quality to its movements that I’m having a hard time describing. The best I can do is say that the Otter seemed to have no momentum at all - it would be heading in one direction, then suddenly it would double over on itself and head in the opposite direction with no hitch in its movements, no evident loss of speed.

The Otter is crunching down yet another Crayfish.

Watching the Otter hunt was like watching the red dot of a laser pointer move over a surface, or watching a shadow pass over the river bottom. Its seeming independence from the flow and push of the river made the Otter seem like a projected image in the water.

Otter manipulating a captured Crayfish.

Sometimes after catching a Crayfish the Otter would just crunch it down as it swam along. Other times it would stop and manipulate the Crayfish before eating it. I couldn’t tell exactly what the Otter was doing  when it handled the Crayfish. Was it pulling off the pincers and eating those separately?

Otter swimming on the surface, eating yet another Crayfish. It seemed as though when the Otter was swimming just along the surface, it would lift its tail up like this when it would lift its head. I imagine that helps to balance the Otter, to maintain its trim as it swims at the surface.

Looking at some of these pictures, you might get the impression that the Otter was often motionless on the surface of the water. That was not the case, the Otter was usually twisting and turning as it swam along, as you can see from the spray of water it’s thrown up in this photo.

The Otter seemed to be working this one pool in the river exclusively. It would hunt its way downstream to the end of the pool, then hunt its way back up stream.

Sometimes as the Otter would swim along the surface it would move its head from side to side, scanning the river bottom.

Sometimes it was hunting so close to the near edge of the river that I couldn’t see the Otter at all - the brush was blocking my view.

I could tell where it was, though, because I could hear it splashing as it hunted, even though I couldn’t see it.

Surfacing and a quick head-shake - another Crayfish captured.

The Otter’s body form a rainbow-arch shape as it dives into the water. Watching the Otter dive from the surface was not a gradual motion like watching as when a Whale sounds, the Otter’s motion was so fast that it was hard to see without a photo.

The Otter’s dives - its tail and hind feet skim just below the surface of the river as the Otter’s head skims above the rocks of the river’s bottom.

I stayed and watched the Otter for forty-five minutes or so. I’ve never been able to actually watch an Otter hunt before. It was a pretty cool thing to see.

I’m also astonished by how many Crayfish the Otter ate. I’d guess it ate at least twenty or thirty while I watched, and it was still hunting when I left.