Are crossbred dogs healthier than purebred?

A mixed breed dog is not more likely to live longer than a pure breed. A bigger determinant of dog life span is the size of the dog. Little dogs generally live longer than big dogs. The most long-lived little dog may live up to twice as long as the most short-lived big dog.

"Hybrid vigor" refers to the fact that if a dog is bred from a mix of breeds it may be less likely to have problems caused by a recessive gene that may prevail in one breed. For this to be likely, any mix of breeds will not do: the breeds must be selected from those that do not have similar prevalent problems. Also, with a mixed breed or mongrel of unknown ancestry, there is no indicator of potential faults that may show up in offspring.

Hybrid vigor may also apply in comparison to breeds that have been inbred. This happens when populations are isolated or small and/or become fashionable. Sadly, fashionable breeds and crossbreeds go through a sudden population growth and are exploited by people who do not look at potential genetic issues when selecting parents. The dogs are also less likely to be carefully selected as a suitable breed by the owners.

To maximize the life span of a dog, keep it healthy and fit throughout its life.