It wasn’t until my friend was bitten by a piranha that I truly began to enjoy my trip to Peru.

For the past few days, I’ve been with a group of friends on a large riverboat making daily excursions into the Amazonian rainforest. Anyone who has seen the Mississippi south of Memphis will instantly recognize the view: a big brown river makes its stately progress past exposed muddy banks, families cruise by on ramshackle skiffs, and the smell of wet, loamy earth is everywhere. Technically, it’s the “dry season” here — but to be frank, everything seems pretty soaked — and it’s the time of year when the river runs low. In the wet season, we were told, the river rises almost to the level of the treetops.