The age-old wisdom holds that a dog ages seven years for every single human year. Well, it turns out the age-old wisdom has some catching up to do. That's because scientists are now claiming that the way dogs actually age is more complex than we humans have previously thought.
Researchers at the University of California now claim that dogs rapidly age in their first two years of existence, quickly evolving from puppies to the equivalent of human middle age. They then experience a rapid slowing of the aging process in their DNA until much later in life.