My 6yos absolutely LOVES it too! The only show I let him watch because he learns so much and just loves finding out all he can about the animals. After each episode, he narrates of his own accord in great detail about the particular animal featured, where it’s found, what it can do etc. etc.
What I’ve been doing is to read to him from Thornton Burgess books to add to what he’s learned from the show, for eg. when he watched the one about beavers, all he could talk about was beavers, he was building beaver ‘dams’ outside, pretending to be a beaver etc. So I read him ‘The Adventures of Paddy the Beaver’ and he loved it. We do this over and above our 106 Days so the only problem is that I can’t keep up with him……