A Baby's Frown

I still don't know why babies make faces so often, wearing a frown like elderly people. At least that's how we interpret such gesture in Spain. We call it La Viejita (old lady). How do you call it when kids frown and they have all these wrinkles on their faces? Here is a very funny video of what they can do, although in this case the frown is somehow different to the one I meant.