As hamster’s teeth grow throughout their lives, they need lots of things to chew on, to prevent their teeth becoming too long. Hamsters kept in captivity can develop overgrown teeth, a condition that affects them if they don’t consume enough hard food to wear down their teeth naturally. Providing them something to gnaw allows them to wear down their teeth naturally. Think of it as a great way of preventing a tooth-related vet bill!
Nibbling a gnaw is a weird sentence, and also a great way of keeping your pet's teeth in good shape
Always make sure the gnaws you provide are safe for hamsters, as some types of wood are toxic to some small animals. Ones sold on stores should be fine, but it's still a good idea to check exactly what they're made of.