Amazon river cruises: Is getting so close to wildlife ethical?

The Amazon. The name sells itself, but choose a cruise carefully, as not all live up to expectations. The mighty 4,000-mile-long Amazon River is on the verge of spilling on to my lap. Water levels are the highest on record and as our dugout canoe, narrow as a carved toothpick, floats through a canopy of entwined treetops, I keep a watchful eye on the Coca-Cola-coloured water lapping at the rim of our boat.