For the study, 40 volunteers listened to different growls recorded from 18 dogs that were guarding their food, facing a threatening stranger, or playing a tug-of-war game.
Overall, participants correctly classified 63 per cent of the growl samples - significantly more than would be expected by guesswork alone, they said.
The human listeners identified 81 per cent of the "play" growls but were less good at recognising food guarding and threatening growls.
Women were better than men at recognising when a dog was being playful or threatening, or feeling fear, researchers said.
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Play growls and food guarding growls also had distinctively different pitch characteristics, 'The Telegraph' reported.
"Our results indicate that dogs communicate honestly their size and inner state in serious contest situations, where confrontation would be costly, such as during guarding of their food from another dog," the researchers wrote in the journal Royal Society Open Science.
"According to our results, adult humans seem to understand and respond accordingly to this acoustic information during cross-species interactions with dogs," the researchers concluded.