What did sailors think about mermaids?

Mermaids are a myth, first heard of 1000 years before Christ. Sailors took them as half fish and half human, and seeing them was bad luck. They were like sirens (another myth) in which when seen sailors were lured to the rocks and their ship would be sunk.

Oddly enough, a very unusual looking (and rather ugly) creature that lives around tropical and sub-tropical waters was once mistaken for mermaids. The dugong, also known as the sea cow, is a lumpy-looking, ungainly sea mammal, and when sailors first sighted these creatures, they believed them to be mermaids.