It lurks just inches below the surface coiled and ready to strike - and yet you wouldn't know it was there.
These remarkable images show the enormous 26-foot (eight metre) anacondas of Mato Grosso in Brazil searching for prey in the murky depths.

Banfi, a father-of-two from Switzerland, said: 'As the snake had just eaten it didn't take much interest in us.

The name literally means 'Thick Forest of the South' and it's easy to see why.
Banfi added: 'At the first moment it's scary because you don't know the animal and everybody says it's dangerous.
'But after a while you understand that nothing happens if you respect the snake.
'I have never been so close to a snake like this before. But I think a small poisonous snake is more scary than a big one. At least you can see the anacondas clearly and know what they're doing.'
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