Such people are rare, but it is the "hairy man" is a classic example of atavism in the school biology. Atavism - a sign of the emergence of the organism that are not his relatives and their immediate ancestors, but when something was available for those of their distant predecessors. Among the examples of atavism in humans - "hairy men", the emergence of caudal appendage, polimastiya - the appearance of additional mammary glands, cervical fistula formation, reminiscent of gill slit mammalian ancestors - fish and amphibians. Further more pictures of people affected by atavism.
Eleven-year-Prutviray Patil Sanglivadi from the village in the Indian state of Maharashtra addressed to the hospital with a unique complaint. All the boy's body (including the face) is completely overgrown with hair.