Dogs age in human years

 You've probably heard the classic dog to human age conversion of 1 dog year = 7 human years but in reality that is a bit of an urban legend that apparently started in the 1960s in a maths text book! Research by the University of Georgia, as published by BBC News (and others) shows a different picture:

For first two years:

• 12.5 years per human year for the first two years for small dogs
• 10.5 years per human year for the first two years for medium sized dogs
• 9 years per human year for the first two years for large dogs

For years 3+:
Small: Dachshund (Miniature) 4.32, Border Terrier 4.47, Lhasa Apso 4.49, Shih Tzu 4.78, Whippet Medium 5.30, Chihuahua 4.87, West Highland White Terrier 4.96, Beagle 5.20, Miniature Schnauzer 5.46, Spaniel (Cocker) 5.55, Cavalier King Charles 5.77, Pug 5.95, French Bulldog 7.65
Medium: Spaniel 5.46, Retriever (Labrador) 5.74, Golden Retriever 5.74, Staffordshire Bull Terrier 5.33, Bulldog 13.42
Large: German Shepherd 7.84, Boxer 8.90

Which means that a small dog is older than a big dog at two human years - but younger at five.

See the full BBC News article, by Ben Carter, Dog Years: How do you calculate a dog's true age? 

Image via Wikimedia Commons