I found this on the BBC Mundo website last week and thought that it was truly astounding and worth sharing.
Ayumu is a chimp at the Kyoto University primate research centre. At 11 years old he can perform numerical/memory feats that are quite amazing.
What feats?
First he learned to count up numbers from 1 to 19 on a screen. Easy stuff for us. But then ...
Ayumu can now see 9 numbers displayed on a screen for 1/2 of a second, have them covered up, and then count them up in order.