Nicole sent a story from the San Diego zoo that highlights bonobo intelligence, as well as just how far we have to go before we can communicate with them:

In an incident that is both heart-stopping and heartwarming, a pregnant bonobo at the San Diego Zoo bit off the tip of her keeper’s index finger Tuesday. But another bonobo rescued the severed tip from her habitat mate and returned it to keepers so it could be re-attached.

The 60-pound pregnant bonobo, also known as a pygmy chimp, was being trained behind the scenes by verbal cues and hand signals to open her mouth for health checkups.

“I guess my fingers got too close to her mouth,” said Mike Bates, the injured senior keeper of the bonobos, a veteran of more than 22 years with the zoo.

After the accident, Lana, the alpha female, heeded her caretakers’ signals to retrieve items that don’t belong in the enclosure, Bates said. Asserting her authority, she retrieved the fingertip and handed it to keepers, who promptly rewarded her with raisins. “I had a really good relationship with Lana,” Bates said.

He acknowledged that bonobos are very intelligent but stopped short of suggesting that Lana actually understood what she was doing. “Luckily she kept it intact. She didn’t think it was food,” he added good-naturedly.

Bates was taken to a hospital, where the fingertip, including the fingernail bed, was reattached, with a 70 percent chance that it will heal. “If it doesn’t, my index finger just may be a little bit shorter than the others,” Bates said. He expects to return to work next week.

Zoo officials theorized that Ikela, the 15-year-old who did the nipping, might not have been feeling well. She also could have been tired of the monitoring of her pregnancy, which is in the first trimester. She has a history of problem pregnancies and stillbirths.

Ikela, born at the Wild Animal Park, lived up to the description accompanying her picture posted outside the zoo’s bonobo enclosure near the Treehouse Cafe. It reads: “Ikela is always pushing the limits of ‘good behavior.’ ”

Lana, the 26-year-old matriarch, likewise, lived up to hers. It says: “She has a strong bond with her caretakers, always wanting their attention.”

[Sign On San Diego: Ape returns finger to keeper]