It’s a question almost as old as time itself: Why do dogs bark so much?

The answer it seems is that humans designed them that way.

“The direct or indirect human artificial selection process made the dog bark as we know,” said Csaba Molnar, formerly an ethologist at Hungary’s Eotvos Lorand University.

Molnar’s work was inspired by a simple but intriguing fact: Barking is common in domesticated dogs, but infrequent if not downright absent in their wild counterparts. Wild dogs do yip and squeal and whine, but rarely produce the repetitive acoustic percussion that is barking. As for wolves, from which modern dog breeds are descended, barking is done mostly by pups.

Many people have made these observations, but Molnar and his colleagues were the first to rigorously investigate it.

Because anatomical differences between wild and domestic dogs don’t explain the barking gap, Molnar hypothesized a link to their one great difference: Domesticated dogs have spent the last 50,000 years in human company, being intensively bred to fit our requirements.

According to Eugene Morton, a zoologist and animal communication expert at the National Zoo, Molnar’s ideas are quite plausible. Morton noted that barking is a very useful type of sound, simple and capable of carrying over long distances. However, it could have been a side effect of humans favoring other, domestication-friendly traits in the wolves from which modern dogs descended.

“Barks are used by juvenile wolves, by pups. It’s derived from a juvenile stage, and kept in adults. That’s probably what we selected for,” said Morton. “We don’t want dogs who are dominant over us. The bark might go along with that breeding for juvenile behavior. Or it could have come with something else we selected, such as a lack of aggression.”

Molnar tested his propositions in a series of experiments described in various journal papers between 2005 and 2010.

Story by Elaine Furst for Dog Files