Cats and dogs do not always live in perfect harmony together, but this doesn’t have to be the case.
According to an article in Science Daily, one reason why cats and dogs often don’t get on together is because they misinterpret each other’s body language. For example, when cats are angry they usually lash their tails, but dogs growl and arch their backs. When a cat avert its head, it is a sign of aggression, but this signifies submission in dogs.
If cats and dogs are introduced to the same house when they’re young - under 6 months for cats and under a year for dogs, they can learn each another’s body language and are therefore less likely to fight and more likely to get along well together.