People have often wondered how man's best friend communicates with humans. Although dog-owners know that dogs use different signals to let their owner know what they want, most people do not realise to what extent. According to an article written by Elaina Zachos for National Geographic, a new study found that dogs use 19 distinct signals to communicate with humans. In the study, which was published in the journal Animal Cognition, researchers filmed 37 dogs interacting with their owners. After reviewing the footage of hundreds videos, the researchers came up with 19 separate signals that…