If we chose to take every paleolithic painting literally - lots of things are real. :) But this is pretty cool - though by the look, this mermaid/man would have to swim sideways. They would've been smarter to go with a dolphin, seal or manatee lower half.
Myths have to come from somewhere. However - Warrior women were not just found in the example given but in many other cases as well, also, they were never just a myth, they have always been history, even if the patriarchy has hidden it as much as possible.