A Dog's Growl Announces Its Size

摘要

Dogs can tell another canine's size simply by listening to its growl, a new study reveals. Peter Pongracz, an ethologist at Eoetvoes Lorand University in Hungary, and colleagues showed 24 canine test subjects images of two dogs projected onto a screen in front of them. One image showed a small dog less than 52 centimeters tall; the other image was of the same dog but projected to be 30% larger. The researchers then played recorded food-guarding growls-from either a large or a small dog-on a speaker placed between the two projected images. The scientists filmed the dogs, recording where the canines looked as they listened to the growls.