Babies and Phones

What is a babies fascination with a phone?  I think it is hilarious.  They will hold up anything with buttons or even mildly shaped like a phone to their ear.  Well actually they hold it up to the back of their head which is even funnier.  I have countless pictures of my children trying to talk on a phone.  I thought of this as I took away my phone from my daughter and then she found my lablemaker and put that up to her head and tried to talk into in.