The yellow-footed antechinus, also known as the mardo, is a shrew-like marsupial found in Australia. One notable feature of the species is its sexual behavior. The male yellow-footed antechinus engages in such frenzied mating that its immune system becomes compromised, resulting in stress related death before it is one year old.

The brown antechinus, also known as Stuart's antechinus and Macleay's marsupial mouse, is a species of small carnivorous marsupial of the family Dasyuridae. The males die after their first breeding season, and the species holds the world record for being the world's smallest semelparous mammal.