We usually work out a dog's "human" age by multiplying by 7. But the maths isn't quite that simple — there are other factors that influence a dog's real age.
According to a study reported by the BBC (United Kingdom), to work out each dog's age we should consider:
Each breed ages at a different rate.
Each breed spends a different amount of time at each stage of life (youth and adulthood).
Small-breed dogs have a short period of youth and a long adult life.
Large-breed dogs are the opposite: they take around two years to reach their adult form and then live for around another 4 or 5 years.
Small-breed dogs live longer than large-breed dogs.
