If a caiman should mistake a gas eel for another fish and attack it, the eel will normally emit two short bursts of gas, which will render the caiman unconscious for around 10 seconds. The gas eel will then make its escape. The caiman will retire to dry land and breathe in fresh air for around 20 minutes, before returning to the water.

Gas eels eat between 5 and 10 pounds of vegetation per day, mainly from plants and trees that have been flooded by the river. Amazonian tribes don’t hunt these fish as their meat tastes rotten, even when cooked, leading these tribes to believe it’s bad luck to eat the meat. They believe any person who eats a gas eel will soon find their own skin begins to rot and they will die a slow, horrible death.

This is an extract from the book Animals Evolution Avoided