The night that we arrived it rained a foot, no kidding. . . This resulted in the tributary that we were fishing to jump up 2 and 1/2 feet the next day, and nearly 5 feet by the end of the trip. Which pushed all the wildlife as well as the fish way back into the trees. But it was still a great trip.
So in short. No we didnt see any river otters, or much of anything besides a few huge caimen (18') some monkeys and some really interesting birdlife.