Do cats or dogs live longer?

Some time ago our herd has expanded by a guinea pig called Hugo. It turns out that the presence of a pet at home is a great pretext for discussing with children the concepts of randomness, distribution functions and distribution in general.

And this is how it started:
— Dad, how long do the guinea pigs live?
— On average from 5 to 7 years (google).
— And do other home pets live longer or shorter?
— Mice have the shortest lives, they live for a year up to three years but then, rodents are short-lived in general. But parrots, for example, they may live up to twenty years, even forty years. And tortoises live even until seventy years.

— What about dogs, how long do they live?
— It depends on the breed – bigger ones live shorter and smaller ones live longer, but usually it is between eight and sixteen years.
— Does it mean that all the dogs die after they reach sixteenth year of life?
— Well… (a longer pause at google+R+ggplot), no, that is only a typical lifespan. Some dogs live longer, some even up to twenty four years.

— And do cats or dogs live longer?
— Well… (a longer pause at google+R+ggplot). Among cats there are many more specimen who live longer than 20 years.

— So who will live longer, Bromba (our friends’ dog) or Mufinka (our friends’ cat)?
— Nobody knows how long will a particular cat or dog live – it depends from the quality of care of their owners and from many other factors. We can say something more about more numerous groups of animals. For example, it one gathered 100 dogs, it could be expected that half of them would live longer than 12 years. But if one gathered 100 cats, then it would turn out that half of them would live over 14 years. And every fifth cat would live over 18 years, what is longer than a lifespan of any dog really.

The presented numerical data is based on the data base VetCompass. It concerns animals visiting the vet, that is animals ”better taken care of”.