If your cat's brushing your hair with his teeth, he could be expressing love and possessiveness. On the other hand, he might be bored, stressed, anxious or sick. Understanding his motives can help you react appropriately.
Pure Pleasure
As strange as it sounds, your cat might just enjoy biting your hair. Some kitties find comfort in licking and gentle chewing, possibly because these activities trigger an endorphin rush. Your feline friend also could be showing you affection in the same way that cats with close family or emotional ties often groom each other. If he bites your hair just after you’ve showered, he might be refreshing his scent on you -- or maybe he just likes the taste of your shampoo.
Stress and Soothing
Your cat could bite your hair as a way of calming herself when she’s anxious. If changes in your routine, living situation or housing have left her feeling insecure, her attention to your hair could be simply a means of reasserting her claim on you and confirming the bond you share. If the behavior doesn’t bother you and occurs in moderation, you can sit back, rest your head and enjoy being groomed.
Compulsion
If your cat's biting becomes compulsive -- if you can't distract him once he's honed in on your hair -- take him to the vet or consult a licensed behaviorist. Identifying possible triggers can help you prevent the biting, but sometimes the behavior moves from being a reaction to an external stress to being a need your kitty is driven to fulfill. If this happens, a behaviorist can help you address underlying issues and channel your cat's urges in more appropriate, healthy ways.
Other Causes
If you have an older cat who’s never shown an interest in your hair before, take him to the vet. His sudden urge to groom your locks could be a symptom of a medical condition such as hyperthyroidism.
Some breeds -- such as Burmese, Siamese, Tonkinese and other Asian cats -- are especially likely to bite hair and chew fabric, paper and other objects. Many behaviorists theorize that cats that were separated from their moms too early tend to bite, chew and lick excessively. Kittens might bite your hair -- along with anything else they can get their little teeth into -- because they’re using their taste buds to learn about the world, just as puppies and kids do.