cat eats carpet!

[mandimoo]

not sure how old he is, vets say approx 1 year old (we rescued him from cats protection league). anyway, he munches on the carpet (and no, im not being rude!), and when ive brushed him and put the hair in the bin he will go and get it and eat it, and he chews on the blanket i let him sleep on and loves to sink his teeth into cardboard boxes too. he's like a naughty puppy. is this normal? i dont ever remember my other cat doing it?