My 7 month old loves chewing on the toothbrush, hippo ears and frog’s tongue, and playing with the seat belt buckle. As with every busy book, she loves chewing on the shoelace that holds the pages together - I make sure it’s double knotted so she can’t pull it all out to a dangerous length. I am so happy with the busy books as it keeps her entertained a lot longer than regular books and allows for independent play :)