They are particularly adept at singing and playing musical instruments and are renowned for their ability to either guide fishermen away from dangerous rocks with their bewitching voices or, sadly, lure ships to an untimely end. In fact, the traditional Irish name for a mermaid is murduchu, which means "song of the sea" or "sea chant."
Sightings have been made throughout the world, but it was during the Middle Ages when symbols of mermaids holding a comb and mirror are first thought to have appeared. For Christians, this came to represent beauty and vanity and the fact that it could prove too much for men and lead them away from stability.
Although not featured so much in the popular tales or sightings, mermen were talked of, too. Together they were known collectively as Merfolk.