The lifespan of a species is determined by a combination of genetic and environmental factors. Genetic factors include the presence or absence of certain genes that are associated with aging and disease, while environmental factors include access to food and water, exposure to toxins and pollutants, and susceptibility to predators and disease.

Humans have a relatively long lifespan compared to many other species, including housecats, due in part to genetic factors such as the presence of telomerase, an enzyme that helps to maintain the integrity of chromosomes and therefore the longevity of cells. Additionally, humans have a relatively low rate of predation and access to medical care and other forms of protection from disease, which also contribute to our longer lifespan.

Early human life expectancy was ably about only 20 years too.