Mermaids are from folklore. Tales of the sea. People thought they were seeing mermaids, but they were really manatees. Mermaids must have been total gugoos.
Do you know of any ancient stories about mermaids?
Sailers thought they were bad luck. Other than "I saw a mermaid one time," I don't think there are a lot of specific stories.
They may have been drinking rum when they mistook a manatee for a mermaid.
Rum is aged in oak barrels. Reminds me of bourbon, which I like a lot. Maybee too much. Whoa, look out for this guy, am I right?
Yes, but I still wonder how the mistake.  Does a manatee even remotely resemble a person in the water?
Well, there's three species of manatees. They all look like very fat, very ugly humans with no legs or arms. If that's what you mean.