A jaguar (Panthera onca) hunts along the river edge. We watched this jaguar for a while as it stalked the edge of the river. The jaguar looked like it was trying to surprise a caiman or capybara. A couple of times it seemed to become aware of a caiman as it would suddenly leap into dense vegetation along the edge of the river. It was not successful when we were watching. When jaguars are successful they will dispatch their prey quickly - often with a bite through the back of the skull. Their name comes from an indigenous word "yaguar" which translates to "he who kills with one leap".
Jaguars once ranged from the south-western US all the way to Argentina. Sadly their range is greatly diminished today and they have an IUCN status of "Near Threatened".