A chimp has invented a back scratcher and the young around him have copied his technique, maybe just for fun.
Field research continues to tell us more and more about the abilities of the great apes. Wild chimpanzees can invent backscratchers, and even more than that – young animals watching this take place can imitate and pick up the behaviour for themselves.
Chimpanzee Invents Back Scratcher
Tinka (a wild male chimpanzee maybe 50 years old) has damaged hands, so he cannot scratch his back or get others to do it for him in the normal way. To overcome this problem Tinka developed a technique where he used the long 'rope' of a liana. He holds one end of the liana in one foot and pulls it taught, and then he positions himself against it and moves so the liana scratches his back for him.
Hobaiter and Byrne, in PLoS ONE, say that 'Adult male Tinka suffers from near total paralysis of both hands, precluding most normal body-maintenance by self-grooming or scratching. Tinka also suffers from a chronic skin complaint and receives low levels of social grooming' and 'he has developed an efficient but highly idiosyncratic alternative (to grooming)'. They go on to say 'Tinka's skin complaint, lack of regular grooming by others, and severe bi-manual disability mean that the liana-scratch technique allows him considerable gains in skin-care and consequent comfort'. In other words he has found a way to overcome his disability.
Young Chimpanzees Learn Liana Back Scratching
Other chimpanzees who live close to Tinka do not need artificial back scratchers (they can either use their own hands, or get someone else to do it for them), but many have copied his technique.
Juveniles who were able to watch Tinka at work began to imitate him, and the technique became a 'fad' among these playful young, and, as Hobaiter and Byrne observe: 'behavioural ‘fads’ have previously been recorded in captive chimpanzee groups, and in one case several juveniles apparently mimicked the strangely hunched style of walking of one older individual'.
This seems to be something that only the young chimps do, as Hobaiter and Byrne note: 'only juvenile chimpanzees show liana-scratch, and then apparently give it up when they become adult'.
Maybe the young are just playing, or maybe they are trying out the technique to see how useful it is. Either they stop playing as they get older, or they realise that hands are better than lianas!
These new findings come as a result of fieldwork, and show that young chimpanzees do not only adopt 'useful' behaviour from others – they sometimes copy for the fun of it.
Reference: Catherine Hobaiter and Richard Byrne, 'Able-Bodied Wild Chimpanzees Imitate a Motor Procedure Used by a Disabled Individual to Overcome Handicap' - PLoS ONE
Image credits: Pixabay.com