Here we see Viki showing considerable dexterity as she climbs up her swing set and attaches a swing rope to hook eyes, then moves down to enjoy her swing. At the time, Viki was perhaps 5 or 6 years old. If she were a human child, her parents should not have allowed her to perform such a dangerous activity: swinging by one hand several feet from the ground to attach a rope. But Viki is built for just such activities: chimpanzees climb trees all the time and sleep in “beds” they make in the trees.

Note that Viki uses her mouth to help get the proper grip on the hook. She holds the end of the hook between her lips and then corrects her grasp on the body of the hook itself. If you watch carefully you will see that she does this before she first tries to attach the rope to the swing. This is an indication of planning on Viki’s part. Smart chimp!