Abstract
We observed a low birth weight chimpanzee (Pan troglodytes) infant (birth weight 790g) and compared the results with observations of other nursery chimpanzees and with those of wild chimpanzee infants in order to establish what basic behavior is, in spite of differences in environment and birth weight. There seem to be three kinds of behavior; (1) that which occurred in the very early period after birth despite differences in birth weight, (2) that which occurred after weight reached the average standard (about 1800g, Graham 1970, Gavan 1952), (3) that which differed according to environment.
