You always thought it was a myth, but Professor Richard Wiseman, of the University of Hertfordshire, England, says it’s a fact: pets and their owners are just like married couples and they get more alike over time.

He asked 2500 pet owners to complete online questionnaires and found they shared such traits as happiness, intelligence, independence and a sense of humour with their companions.

“For years owners have insisted their pets have a unique personality” he told London’s Daily Telegraph. “Not only does this work suggest they might be right, it also reveals people’s pets are a reflection of themselves. Similarity promotes liking in humans. Research has shown couples that are like each other stay together longer.

“Extending this to the animal kingdom, I think it is likely someone who is fun and playful is more likely to go for a dog, for example.”

Wiseman says cat lovers are dependable and emotionally sensitive, reptile owners are independent and fish owners stand out as the most contented of individuals. “Around 60 per cent think their fish have a sense of humour,” he said. “I’m not sure how that works. On the other hand, people who keep lizards and snakes don’t think their pets have a sense of humour, and those owners are pretty humourless, too.”