If you're looking for animal books for 7 to 9 year olds, let me introduce you to these two:

The Hodgeheg by Dick King-Smith from Foyles

Max is a hedgehog.  He lives with his family in a nice home, but it is on the wrong side of the road from the park.   There's a pond in the park, with lots of slugs, worms and snails.  

The road is very dangerous but Max makes it his mission to find out how hedgehogs can cross safely.  He gets hit on the head in his efforts to find a way, and consequently mixes his words up.  Max thinks:  if people can cross the road safely, hedgehogs should be able to as well!

Max sets out to solve the problem and of course he does - enlisting the help of a lollipop lady and another hedgehog. 

The Last Polar Bears by Harry Horse from Foyles

I loved this book with the bumbling grandfather and his dog called Roo, as they head off to the North Pole in search of the last polar bears.   Why it should be kept for children, I don't know.  The story of grandfather and Roo are told through a series of letters.   We hear how Roo told the most ridiculous stories, how she changes her mind about going to the North Pole, about the wolves who keep them up all night with their singing, and the penguin injured by one of grandfather's golf ball.  (So there are inaccuracies in the story because there aren't any penguins in the Arctic - they are all in the Antarctic.  No matter, I loved the story anyway).  

Both take the reader into the natural world in an easy reading style, which I hope children (and adults) will enjoy.