Why do dogs bark when ever they hear another dog barking?

If two people are in a room, and one speaks, what does the other one do?

If they are like my dogs, i think they do it just to hear their empty heads rattle. :)

I don’t know. I just wish they’d stop it.

I don’t think you can assume there is nothing there. There is nothing that you sense, but dogs hearing is better than people’s.

Also, they alert for different reasons than we would.

Dogs hear a lot of things we don’t hear. Maybe they are both barking at the same thing, but we don’t hear it.

I always thought they were just barking for the sake of barking.

I’d like to give them credit for having super sensory perception but sometimes one dog will bark at something on television and the other will come out of a dead sleep to join in with obviously no idea what the fuss is about.
It’s a social thing and I don’t believe a bit of thought goes into it.

They can’t have Fluther accounts, so it’s the only one way they have of giving lurve.

All animals communicate especially amongst their own species.
In your case your second dog is probably barking as a form of re-assurance towards the dog that barked first.
http://en.wikipedia.org/wiki/Animal_communication

Because they’re a sociable pack animal who just love to chat. Much like our good selves…..only we can’t lick our own genitals, unfortunately :¬)