Mermaids and mermen are said to save sailors from death during shipwrecks. They help sailors onto pieces of the wreckage, then guide this to the nearest shore. They’ve also been said to offer healing upon reaching shore, and to bring the sailor fish and other supplies that can be found in the sea while the sailor recovers.
If a sailor cannot be saved by being towed to shore, or is already dead, mermaids and mermen have been said to protect the bodies of sailors from predators, and to bring the sailor’s body back to land.
Merpeople do not speak to the sailors they rescue, though they seem to understand what is being said to them. They have their own language that they use amongst themselves.
It is believed that merpeople reproduce and suckle their young like mammals, and that their genitalia are hidden in slits in their tails, like many fish. But this mystery has plagued scholars for all time and they have never received a concrete answer of course. It is also theorized that they mate for life, but there is no known evidence of this. It’s likely an application of human societal ideals to a species that seems very human despite its differences.