The dogs and cats do, let us humans do it

http://www.sciencedaily.com/releases/2008/09/080908135916.htm

Dogs And Cats Can Live In Perfect Harmony In The Home, If Introduced The Right Way
ScienceDaily (Sep. 9, 2008) — Thinking about adopting a perky little puppy as a friend for your fluffy cat, but worried that they’ll fight -- well, like cats and dogs?

Think again. New research at Tel Aviv University, the first of its kind in the world, has found a new recipe for success. According to the study, if the cat is adopted before the dog and if they are introduced when still young (less than 6 months for kittens, a year for dogs), there is a high probability that your two pets will get along swimmingly.
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One reason for the fighting might have been crossed inter-species signals. Cats and dogs may not have been able to read each other’s body cues. For instance, cats tend to lash their tails about when mad, while dogs growl and arch their backs. A cat purrs when happy, while a dog wags its tail. A cat’s averted head signals aggression, while in a dog the same head position signals submission.

In homes where cat/dog détente existed, Prof. Terkel observed a surprising behavior. “We found that cats and dogs are learning how to talk each other’s language. It was a surprise that cats can learn how to talk ‘Dog’ and vice versa.”
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Once familiar with each others’ presence and body language, cats and dogs can play together, greet each other nose-to-nose, and enjoy sleeping together on the couch. They can easily share the same water bowl and in some cases groom each other. The far-reaching implications of this Tel Aviv University research on cats and dogs may extend beyond pets -- to people who don’t get along, including neighbours, colleagues at work, and even world superpowers.

“If cats and dogs can learn to get along,” concludes Prof. Terkel, “surely people have a good chance.”