The study of 1000 domestic animal owners in the south of England also uncovered examples where jealous dogs acted as 'uninvited chaperones' between couples sharing romantic moments.

The research was done by University of Portsmouth psychologist Dr Paul Morris and colleague Christine Doe, and will be presented at the BA Festival of Science in Norwich, on Thursday 7th September.

It challenges the long-held scientific belief that only humans and chimpanzees are able to experience secondary emotions such as jealousy, guilt, shame and pride.

Dr Morris, who is an animal behaviour expert, said dog owners showed 'remarkable consistency' in reporting jealous behaviour.

He said dogs could feel intense pangs of jealousy and animosity when in a 'love triangle' involving the carer and another person or animal.

'The study set the typical behavioural index of jealousy as pushing between the carer and the third party, and this is what happened more than 80 per cent of the time,' Dr Morris said.

'The significant aspect of these findings is that most academic theorists agree this behaviour is appropriately labelled as jealousy.’

Dr Morris said it was readily accepted in the scientific community that dogs, cats, horses and other non-primate animals experience primary emotions such as anger, anxiety and surprise.

Secondary emotions such as jealousy, pride, embarrassment and shame are considered to be the exclusive domain of humans and perhaps chimpanzees as they have the cognitive capacities required to support the complex range of secondary emotions.

But this thinking, Dr Morris said, might have to be revised.

'The study systematically investigated evidence for a wide range of emotions including jealousy, pride and guilt in a wide range of domestic animals,' he said.

'Our study provided good empirical evidence that has convinced many scientists that dogs at least demonstrate behaviour that is very like human jealousy.

'The data clearly suggest that complex emotions are present in a wider range of species than once thought and that animals do indeed have rich emotional lives.'

Dr Morris has been invited to present his paper 'Proud Horses and Jealous Dogs: Evidence for Secondary Emotions in Non-Primate Species' at the BA Festival of Science.

The Festival will be in Norwich from 2-9 September, bringing over 300 of the UK’s top scientists and engineers to discuss the latest developments in science with the public. In addition to talks and debates at the University of East Anglia, there will be a host of events throughout the city as part of the Science in the City programme.

Dr Morris has delivered the research findings at a recent conference in the United States held by the International Society for Research on Emotions.

Source: University of Portsmouth