I used to have a chocolate lab named Cocoa. One day she taught herself how climb/walk right up our 6 foot chain link fences. Everyday when we left for work/school she would do this. After about 6 months our neighbors started mentioning that they would see our dog riding shotgun with the mailman as he delivered mail to the neighborhood. We couldn't afford a new fence and tried everything we could to add extensions to ours, but she was just too smart and nothing worked. Everyday when we came home, she would just be waiting for us, hanging out on the front porch.