Itebero the nutcracking gorilla

On the heels of last month's paper on walking-stick use in gorillas, the AP reports on nutcracking by a juvenile gorilla at the Dian Fossey sanctuary in Congo.

Alecia Lilly, a primatologist in Rwanda who worked for over a decade with a colony of captive gorillas in South Carolina and has seen Itebero at work, said most learning among gorillas occurs through imitation. But Itebero had no instructor, alone in her sanctuary with her keeper.
"Itebero is remarkably proficient at cracking nuts," Lilly told The Associated Press by phone. "It takes most chimpanzees many years to reach similar levels of proficiency."

There is certainly a lot of emphasis given to the "independent invention" aspect of such tool use instead of just "learning from humans." Most primates can learn to do a lot of things by watching humans that they never do in the wild. If anything, the potential to learn tool use is overdeveloped compared to the opportunity to learn tool use in the wild. That points to the hypothesis that such potential exists for other purposes, such as social learning.

But that leaves unexplained the exceptional individual that develops apparently "advanced" behavior on her own. Is such behavioral variation analogous to variation within humans? Or is there more of a chance aspect? Of course, humans have a chance aspect to exceptional behavior also...