Whether the creature itself is male is unknown, but the shape it takes certainly is! By day, it is a simple river dolphin. Traditional folklore describes the night-time transformation of this dolphin into a purportedly stunning young human man, who emerges to seduce and impregnate a woman. He returns to the river by daylight, and becomes a dolphin once more, simple as that.
An article on unexplainable.net, "Mythical Creatures of the Water: Shapeshifting Dolphins" by Yona Williams, splits the Boto dolphin and the Encantado into two different beings, whereas other sources indicate that Encantado is simply the Portugese term for the same creature. Williams seems to draw her distinction at the category of magical prowess: where the Boto dolphin is the creature of folklore that shifts from dolphin to man for the purpose of impregnation, the Encantado seems to have access to a snake form as well. She describes the Encantado as coming from an underwater paradise, and as either a spirit or a shapeshifter depending on which source is being referenced. Further, she characterizes the Encantado with "impressive musical abilities, seductive qualities, and a thirst for partying," and while she claims that this makes it similar to European fairies (and leaves her argument with no proof), I am more inclined to contrast it against mermaid lore. While fairies by large do enjoy a good revel, they seem to be in it more for personal interest or for prankster-like amusement with the occasional liasion, rather than the strict goal of sex that the Encantado pursues.
There is a theory (cheers, Wikipedia) that this South American myth originated out of a need to explain or otherwise cover up the incestuous couplings that were occurring in small, isolated groups of people along the river. Entangled Edens, a book by Candace Slater, muses that the Encantado in Amazonian folklore may represent white people or gringos, who are "almost always strongly negative personas in contemporary Indian narratives." In an interesting discussion as to why the Encantado is not as commmonly reported today, she interviews a native named Pedro Paulo who declares:
"Do you think that the Cobra Norato is going to rent an apartment
and install a telephone? No, no, the Encantados aren't going to live in
dirty rivers into which people throw old Cokebottles and all sorts
of other garbage. They won't put up with a place all full of factory
fumeswhere your eyes itch and burn any time of night or day.
No, they like peace and quiet, they like to bathe in clear rivers and
to stroll through the woods at dawn. You can still find a few here
in the Areia Grossa...but they're getting to be fewer and fewer
as more houses crop up where once there was
nothing except trees and sand." Slater, 72.
and install a telephone? No, no, the Encantados aren't going to live in
dirty rivers into which people throw old Cokebottles and all sorts
of other garbage. They won't put up with a place all full of factory
fumeswhere your eyes itch and burn any time of night or day.
No, they like peace and quiet, they like to bathe in clear rivers and
to stroll through the woods at dawn. You can still find a few here
in the Areia Grossa...but they're getting to be fewer and fewer
as more houses crop up where once there was
nothing except trees and sand." Slater, 72.
It is very sobering to consider how many magical beings the progress of humanity has killed off. In fact, if there is any theme more common than that among fairy-lore, shifter-lore, or talking-creature-lore, then I have yet to find it.
When did the birds stop talking to people? Slater asks another native, and he responds: "In that time before people started burning down the forest and the Encantados had to leave."
