Wildlife photographer Kevin Dooley, 58, watched as the jaguar landed on the small crocodile, known as a caiman, before wrestling it to death.
Mr Dooley said the jaguar 'never once broke its gaze' from the caiman that was swimming in the river below in Pantanal, Brazil.
After an hour of waiting, Kevin said the cat, 'which kept as quiet as anything', then pounced on the caiman when it began to swim towards a tree.
He said: 'It was amazing to watch. The jaguar jumped into the water and wrestled with the caiman, eventually killing it.
'He then dragged it up the tree, as though it had got his dinner.