Legends of these half-human, half-fish humanoids have circulated for millennia, even as far back as 5000 BCE. It has been widely suggested or implied that manatees or dugongs could be behind the myth of the mermaid.
An example supporting this theory would be that Christopher Columbus had logged that he had seen mermaids on his journey to America, but thought they would be more attractive. These large aquatic mammals are notable for the way in which they carry their young, cradled in their arms much as a human would carry a baby.
It is possible that sailors seeing these unfamiliar beasts for the first time, would assume that they had in fact stumbled across some sort of humanoid species, and consequently spread their accounts of the sightings through their homelands on their return from voyages. It has even been posited that the traditional picture of a mermaid with long flowing hair could be attributed to manatees breaking the ocean surface beneath patches of seaweed, and giving the unfamiliar observer the impression of having long hair.
Sightings from first-hand witnesses generally describe mermaids who do not talk and have green or black hair.
