| CHIMPANZEES BOSSOU AND NIMBA

Mother

Acquiring a taste for nuts

Mother

Observing closely

Showing an interest in stones

Stealing her sibling

Experiencing every step  in Learning-nut-cracking process

Selecting one

Stealing the mother

Trying to crack the mother

The challenge of combining the stones and the nuts

Education by master-apprenticeship

Putting several nuts on the anvil stone

First success

Accidentally hitting her foot

The adults who cannot use stone tools

Young chimpanzees who cannot use stone tools