<sod>The [[life expectancy]] of a [[cat]] that is kept indoors is typically 12–16 years. The life expectancy of a cat living outdoors is typically 2-5 years. Cats living outdoors<ref>{{Cite web|url=https://www.somerzby.com.au/blog/cat-questions-faq/|title=50 Most Popular Cat Questions Answered|last=|first=|date=|website=Somerzby|publisher=|access-date=}}</ref> usually have a much shorter life expectancy due mainly to external environmental conditions and dangers such as traffic accidents, intentional acts of violence, poisoning, diseases from other cats, and fighting with other animals. However, some cats may attain the age of 21 years or more.<ref>[http://cats.about.com/cs/catmanagement101/f/lifespan_cats.htm "What is the life span of the common cat?"], [[About.com]].</ref> By comparison, the average life expectancy of [[Life expectancy#Humans|humans]] in the United States at birth in 2014 was 79.56 years.<ref>[https://www.cia.gov/library/publications/the-world-factbook/rankorder/2102rank.html CIA - The World Factbook -- Rank Order - Life expectancy of humans at birth].</ref> A one-year-old cat is roughly comparable, in developmental terms, to a 15-year-old-human. Subsequent years of a cat's life add progressively fewer years to its human age equivalent, so that a 15-year-old cat is roughly comparable, developmentally, to a 76-year-old human.<ref>[http://cats.about.com/cs/healthissues/a/agechart.htm "Cats Age Conversion Chart"], [[About.com]].</ref><eod>
<sod>The [[life expectancy]] of a [[cat]] that is kept indoors is typically 12–16 years. The life expectancy of a cat living outdoors is typically 2-5 years. Cats living outdoors<ref>{{Cite web|url=https://www.somerzby.com.au/blog/cat-questions-faq/|title=50 Most Popular Cat Questions Answered|last=|first=|date=|website=Somerzby|publisher=|access-date=}}</ref> usually have a much shorter life expectancy due mainly to external environmental conditions and dangers such as traffic accidents, intentional acts of violence, poisoning, diseases from other cats, and fighting with other animals. However, some cats may attain the age of 21 years or more.<ref>[http://cats.about.com/cs/catmanagement101/f/lifespan_cats.htm "What is the life span of the common cat?"], [[About.com]].</ref> By comparison, the average life expectancy of [[Life expectancy#Humans|humans]] in the United States at birth in 2014 was 79.56 years.<ref>[https://www.cia.gov/library/publications/the-world-factbook/rankorder/2102rank.html CIA - The World Factbook -- Rank Order - Life expectancy of humans at birth].</ref><eod>