Much research has been done to determine why kids do some of the silly things they do. With respect to chewing on their hands, there are a few theories. No one knows for sure why kids place things in their mouth more so than adults do. Sigmund Freud's theory of the oral stage for young infants stated that they are fixated on their mouths. This is because most of their existence is related to getting their next meal. As kids grow, some of them keep putting things in their mouth beyond when they are only interested in eating. This was thought be because the kids were weaned either too quickly to too late. To be completely honest, modern medicine does not buy into Freud's theories anymore. They are interesting, but not applicable any to practice. I suggest that before your next pediatric visit for your toddler that you write down a list of questions to bring up with him or her. You can get his or her take on the whole oral fixation theory. Perhaps your toddler's doctor
has an opinion and a remedy if you ever run into that problem. Good luck.