Shortest-lived mammal

The world's shortest-lived mammal is the Müller's giant Sunda rat (Sundamys muelleri). Native to forests across much of south-east Asia, but particularly Indonesia and Malaysia, this large arboreal rodent has a maximum recorded lifespan of only six months in the wild. Specimens in captivity have lived for up to two years, but captive specimens of many species live longer than their wild counterparts because they do not face the threat of predation and the necessity to find food for themselves like wild animals do.

Certain other mammalian species exhibit very short maximum lifespans in the wild. In the case of southern Africa's forest shrew Myosorex varius and North America's smoky shrew (Sorex fumeus), for instance, this is around one year. The common shrew (Sorex araneus) has also been estimated to live for only 12 months on average.

Male specimens of the brown antechinus (Antechinus stuartii), a species of tiny shrew-like marsupial mouse endemic to Australia and famous for its males dying from exhaustion after mating for their first and only time, typically live no longer than 0.9 years. This makes this species the world's smallest semelparous mammal (i.e., one that reproduces only once in its lifetime).