Observations were made of a group of adolescent chimpanzees (Pan troglodytes) living in one-acre field enclosure. In 1,200 h of observation, we observed 341 copulations involving six individuals. 34 elements of copulatory behaviour were described and recorded, including facial expressions, vocalisations, gestures, postures and locomotion. Frequencies, combinations and sequences of the elements were extracted in analysis. The results emphasise individual differences and the rapid ontogeny of copulatory behaviour elements.