How and why are animal years calculated?Asked by: Jenny BrewerHaving numerous animal-lovers in my family, I have often heard about and accepted the concept of animal years, but never properly understood why or how it is calculated - so I was keen to investigate how the system works. Animal years, or ‘animal ages,’ are a system used by vets and pet owners to assign an age to an animal in comparison to a human’s life span. The well-known metric used for cats and dogs equates each year lived by an animal to seven years of human life, so for example when your dog or cat has lived for three years, it is said to be 21 years of age in human years.
Many find this system inaccurate, as noted by final year veterinary student at Glasgow University, Anna Beber.
‘Animal ages (e.g. for every year a dog is alive it is the equivalent of 7 human years) … [is] a kind of nice way to show that animals age much faster than humans, but it’s not accurate at all because when dogs and cats (and most other animals) develop, they mature really quickly in their first year.’The speed at which dogs and cats mature in the first few years of their life is much quicker than that of a human. Most cats and dogs are considered adults by the age of 2, so with the 7-year system this would mean the animal was the equivalent of 14 human years, which is misleading. New systems have been created to solve this problem such as the Cat years scale at
Purina.co.uk and the Dog scale at
www.calculatorcat.com. However different breeds have different life expectancies, making it impossible to create an accurate scale.
Can an animal’s level of maturity ever be related to that of a human’s? I would say no, as a human develops in different ways to other animals. A one year old child my not be able to feed itself or chase a ball around the room, but its cognitive skills far out-weighs that of a young dog or cat. Comparatively, a seven-year-old child possesses abilities that animals can only have in fantasy films such as ‘Cats & Dogs: The Revenge of Kitty Galore’.
The concept of ‘animal years’ is a loose comparatives system, as there
‘is no reliable scientific method for calculating exactly how old [a] cat [or dog] is in human years.’ (
Purina.co.uk). Overall the system can be seen as a folk science and in fact should not be used for literal comparison. Human years are calculated by the passing of an earth rotation around the sun, and maturity accrues in humans at different times, based on environment and genetics. We have markers or milestones that create a system of maturity, from childhood to teens to adulthood, but these are essentially loose concepts, so relating them to another animal is even more tenuous. Vets use the animal year system to gain a better idea of where an animal is in its life cycle, using this to help understand what health problems could arise. Though the system is largely inaccurate, it helps to have this direct comparison so we, as humans, can relate to our furry friends.
