The emotion conveyed by a dog's bark often seems obvious to its human companions, but new research shows just how clear the message can be -- at least, to other dogs

Dogs "express basic emotions

the scientists made recordings of Hungarian Mudi dogs barking during two different situations

when a stranger entered the property

when the dogs were tethered to a tree and left alone

scientists next outfitted each of the listening dogs with a heart rate monitor

the sound of all dog barks caused a listening dog's heart rate to jump

hearing a certain type of bark consistently over time stabilized the heart rate

Previously, other researchers thought domesticated dogs barked primarily for our benefit, since neither adult wolves nor feral dogs bark

it's likely that the dogs understand the different contexts producing the barks