They say that the pets use different barks to try to explain to humans how they are feeling.

Researchers found pooches use noisy woofs when they are defensive, insecure aggressive or distressed. But they bark musically when they are happy.

Experts have long suspected there may be more to barking as it's much more common in domestic dogs than wild dogs.

Wild dogs, including wolves, foxes, jackals and coyotes, tend to whine and howl more.

They generally only bark to show aggression, though as puppies they do bark when they're playing.