It is not really normal, but they do tend to try and eat various objects around their enclosure. Is he actually taking bites out of it, or is he merely biting it and not ingesting anything?
Hes less than a year old and the log is hid hide, the half log thing you get at the pet store. He has had it in his room from day 1, just day before yesterday he dug a hole next to it and started nibbling on the side of the log
I find it interesting people are saying this isn't normal... Every clutch I've ever had tries eating the log. They don't succeed so I don't worry about it.