If you've never been, and you're in the area, it's worth a visit. They host events that are great for kids and a lecture series in the antique lecture hall. I've attended some really interesting ones in the past. The collection has taxidermy animals, skeletons, insects, fossils, rocks, shells, etc... There's a particularly interesting case that shows the process of making the taxidermy animals. All of us grabbed clipboards and did the scavenger hunt they provided.
I like supporting these 'hidden treasures' which Philadelphia seems to be full of, so we picked out some things from the gift shop, one of which was this awesome book.
Sarah Asper-Smith 2010
Another animal ABC book but this time with bold graphics and the name for animals in a group. Now we know that a group of rhinos is called a "crash" and a bunch of turtles is a "bale". Really fun stuff!
It's funny how appropriate this one (and the hippo one) is!
Other ABC Books:
The City-Country ABC
The Underwater Alphabet Book