"Gorillas hold 'wake' for group's leader"

After reading this article over at CNN, I had to wonder: did the gorillas even know that their leader was dead?

"It was like they used to do in the exhibit, lying side by side on the mountain," keeper Betty Green said.
[...]
"Koola inspected Babs' mouth for a while, then held her baby close to Babs, like she loved to do the last couple months, letting Babs admire her," Green said.