Here at Chez BA we have two dogs and a cat. They get along, kinda. There's a lot of sniffing followed by swatting, for example, and the occasional spirited if short-lived chase.
But there is also harmony. Sometimes. It's common for the animals to fall asleep together on the couch, and it's usually extremely cute. I saw Canis Major and Leo (not their real names) napping on the couch recently, and thought what a sweet picture that would make. But when I took the shot...
This explains a lot of things, including the worried look on Canis Major's face, and the recurring red marks on my arms.