The first mermaid-like figures appeared around 30,000 years ago in Paleolithic cave paintings. The earliest written record is from 1000 BC in Assyria. In many tales, they are seen as omens of storms, shipwrecks, or, in some European stories, as keepers of treasure or helpers to sailors. While no evidence of aquatic humanoids has been found, fictional biology often depicts them as mammals with large lung capacity, enhanced diving reflexes, and significant subcutaneous fat for coldwater insulation.
