All kinds of animals can be friends. I've seen dogs and ducks, dogs and elephants, as well as dogs and lions together. See the common denominator here? D-O-G-S! Not only are they man's best friend, but dogs are best friends to a lot of other animals, too.
I believe I can tell if a dog is friendly by just looking into his eyes. Much of a dog's aggression comes from fear or abuse. If one can get through that self-protective shell, then the true, sweet dog is underneath.
Dachshunds . . . you gotta love 'em! (Because they certainly love you.)