New York, Feb 23 (IANS): Not only humans, but their canine friend too have moods and personality traits that shape how they react in certain situations, says a new study.

The study revealed that, like humans, dogs' personalities are likely to change overtime.

Dogs' personalities can also predict many important life outcomes suggesting that canines' personalities influence how close they feel to their owners, biting behaviour and even chronic illness.

"When humans go through big changes in life, their personality traits can change. We found that this also happens with dogs and to a surprisingly large degree," said lead author William Chopik Professor from Michigan State University in the US.

"We expected the dogs' personalities to be fairly stable because they don't have wild lifestyle changes humans do, but they actually change a lot. We uncovered similarities to their owners, the optimal time for training and even a time in their lives that they can get more aggressive toward other animals," said Chopik.

While older dogs are much harder to train, the right time to teach a dog obedience is around the age of six when it has crossed the puppy stage, but before it is too set in its ways, Chopik noted.

Exposure to obedience classes to dogs and training were associated with more positive personality traits across the dog's lifespan, Chopik suggested.

The study, published in the Journal of Research in Personality, surveyed owners of more than 1,600 dogs, including 50 different breeds.

The findings showed that dogs and owners share specific personality traits indicating that extroverted humans rated their dogs as more excitable and active.

Owners high in negative emotions rated their dogs as more fearful, active and less responsive to training.

Further, owners who rated themselves as agreeable rated their dogs as less fearful and less aggressive to people and animals.