Jakob, our little Houdini

This morning as I was getting up and around I heard Jakob waking up, next thing I knew he had escaped the confines of his crib for the first time. He's only 9months old! I was shocked! Maija never got out of the crib and Anika didn't even try until she was nearly two. Should I chalk it up to boys being boys? I guess it's time to lower the mattress.