Alex and his security blanket

A few days ago I sat in on a training session with one of the nursery raised chimps called Alex. He is five years old, a juvenile, and very energetic. The nursery chimps (Alex plus two females) were raised by humans for several years at the zoo. One researcher, Suzanne, spent 8 hours a day with these guys while others took the night shifts. As a result, there are strong attachments both ways between the researchers and these animals. In the past year or two, the zoo set up a separate chimp group in order to integrate the nursery chimps into normal chimp life here. The three A's (Alex, Alexandra and Annet) now belong to a group with 4 other chimps who were mother raised in the Chimp A group. This is working out well, but the 3 A's still love human contact. They even turn their backs to certain researchers at the bars of the indoor cages - a chimp behavior meaning "groom me, please." [Note: the development of the 3 chimps is documented in an SRCD monograph that came out in 2005, Tomasello and ???].

On this particular day, Alex was being trained to imitate a human. He had already learned about 7 gestures such as tap your head, smack the floor, pat your tummy, etc. Several more were proving very difficult such as raise your arm and shake your wrist. Alex would do a few imitations getting food each time, then get up and walk around or climb the cage, then come back for more. I noticed that he carried a piece of burlap sack with him and asked about it. According to Josep Call, he has kept that security blanket with him from his nursery days. Apparently, this kind of attachment to an object, common in human children, only occurs with nursery raised chimps. Josep believes the absence of a mother underlies the phenomenon.

Alex became frustrated with the imitation game after about 15 minutes. The researcher decided to stop the training and we got to play with him a bit. Alex remained in his cage area; he is small but very strong and I could tell when he casually banged on the plexi glass separator - a playful tap would knock you off of your feet. So we ran from side to side of the cage as I frequently do with my dog. And we tugged at his burlap blanket. I even got to feed him through the grates, directly into his mouth. Generally, you would never do this with a chimp - you place food in their hands. But Alex is a special case.