Is This a Boy Thing?

Ever since having Trace 10.5 months ago I have been looking for differences between raising boys and girls. I think I may have found one, besides the obvious of course. The past couple of weeks, Trace has begun sliding objects across the floor. It doesn't matter if it is a book, a lid, a puzzle box, or a school bus. It is the cutest thing. He will get two books out and put one under each hand and just begin pushing them across the carpet while on his knees. I recently gave him the school bus and he thinks that is pretty fun. He enjoys pushing it all over the house. So I ask, is this a boy thing, because my girls never did this?