"They ate his body, nearly all of it, and just left his head and some remains," Limpopo police spokesman Moatshe Ngoepe told AFP.
The man's motives for trespassing are still unclear. He was killed in an area known for rhino poaching.
Authorities are trying to figure out if the man was there to illegally kill lions when he was attacked.
A loaded hunting rifle was found near the body on Saturday morning. Police are trying to establish the victim's identity.