We came upon this otter as soon as we pushed off from the shore. She seemed agitated and snorted at us. I too became agitated because I was sure we were too near to the campsite . She brought out another otter, bigger and greyed around the muzzle. They both made loud snorts and had this look on their faces. According to what I can find the Giant River Otter has a complex assortment of sounds and may be the nosiest of all the otters. An "explosive" snort was one of the sounds mentioned and this is what they were offering us.