“Yes, I would say that is most likely a human with some birth defects.”
But...
“The locals tracked it to a nearby lair or nest where they found three more creatures of similar size.”
How could that be?
Either, somebody lied to make a good story (most likely), or the primitive locals toss deformed babies out into the jungle to fend for themselves, like we used to when we were primitives (less likely).
Quadruplets?