Non linear aging of horse and humans
Young horses age much faster than humans, with horses reaching pony puberty by age two (compared to a human at age 10). As athletes, horses are over-the-hill as racing horse at age 6, while humans are too old to compete as runners by age 30.
There are also other factors in horse age compared to human age, namely advanced in medical science and the size of the horse. Miniature horses commonly live to be at least 10 years longer than large horses, just as small dogs can live almost twice as long as large dogs.
Angel, a miniature horse who lived to be more than 50 years old
Medical science increases horse age
Advances in Medical science has had a huge impact on horse longevity. A mere 40 years ago horses rarely lived to age 25 because of the devastating effects of encysted strongyles, the fancy name for the worms that used to ravage the innards of horses. Today, Ivermectim and Panacur have single-handedly increases the lifespan of horses by a decade.
Here is the non-linear chart comparing horse years to human years.
Horse age --- Human age
1 year ---------6 years
2 years -------13 years
3 years -------18 years
4 years -------20 years
5 years -------24 years
7 years -------28 years
10 years ------35 years
13 years ------43 years
17 years ------53 years
20 years ------60 years
24 years ------70 years
27 years ------78 years
30 years ------85 years
33 years ------93 years
36 years ------100 years
On-average, miniature horses may live one-third longer than large horses.
This size-longevity relationship is the same for dog breeds. For example, a Rottweiler may live to be 12, while a Yorkie may live to be 20 years old.
Janet with Black Beauty, the Guinness Book of Records world’s smallest horse from 2001 to 2008.