Barbering themselves?

[PopcornPigs]

Ok so I've heard of and seen guinea pigs barbering other guinea pigs.
But I've groomed Willy today and he's a peruvian? I think anyway. But one side of his body is really long and flowing, and probably about 2 inches+ long whereas the other side of his body the hair is from 2cm - 1 inch long? I don't think it was like that before :{
Why would he do this? (If he has)

 

[Wiebke]

Guinea pigs can give new hairdos in amazingly short time. They can barber other piggies, but some will barber themselves, too. You can usually distinguish a self-barber as they will rather eat holes where they can reach best with their mouths on their own bodies while a haircut from another piggy is often more even.

http://www.oginet.com/pgurney/barbering.htm