After being photographed mating face-to-face, Leah now has two historic firsts to her name.

The western lowland gorilla's first claim to fame was her use of a "walking stick" (shown in a video still above). The feat was hailed as the first evidence of a wild gorilla using a tool in 2005.

So is Leah a particularly progressive gorilla? Perhaps.

But conservation biologist Thomas Breuer, who has been observing Leah in Congo, also suggests that her behavior might be rare or simply rarely seen.

"What we know about these gorillas is just a tiny bit," he said.

"So I'm kind of hesitant to say she's particularly special. I think we're [beginning] to understand the flexibility of their society and natural behavior. In time we may see more."

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