My 7 y.o. girl would love to have a deer as a pet. We see them all the time here in Burbank, but they are mule deer— and if I recall, mule deer will kick the living crap out of you if you get too close.
My 2 yr old Lab would like to have a deer for a pet too. Or a squirrel. Or a bunny. The cat is too independent and doesn't want to be the dog's pet.