Scientists change how we calculate dog years

Dog lovers have been using the wrong method to calculate their pet's age. Researchers say the practice of finding a dog's age in human years by multiplying by seven is incorrect. They have come up with a new formula that precisely finds out a dog's age. The new method needs more than simple mental arithmetic. It compares the changes of the DNA of dogs and humans. Scientists say DNA analysis is the best way to measure the ageing speed of dogs.

Researchers tested blood from 105 dogs. After some number crunching, they created a graph to show dogs and people age at different rates. A one-year-old dog is similar to a 30-year-old human, while a four-year-old dog is like a 52-year-old. A researcher said: "A nine-month-old dog can have puppies, so we already knew that the 1:7 ratio wasn't an accurate measure of age." He added that different breeds of dog age at different speeds.