I saw a great video on YouTube recently showing them work out displacement and stuff with u shaped pipes with water in them.
They reckon they're comparable with dolphins and chimps in terms of intelligence. They know traffic light sequences and use them to drop and retrieve nuts after cars have cracked their shells.
( Slippery Mick ‏, Sat 18 Mar 2017, 20:56, archived)

chimps are apparently going through their own stone age right now

( Moon Girl Technologies horrendous beanbag, Sat 18 Mar 2017, 20:59, archived)

Really? Got a link where I can read up on that?

( Slippery Mick ‏, Sat 18 Mar 2017, 21:07, archived)

www.bbc.co.uk/earth/story/20150818-chimps-living-in-the-stone-age
( Moon Girl Technologies horrendous beanbag, Sat 18 Mar 2017, 22:13, archived)