Dusky antechinus are small marsupials. They were described by English naturalist George Robert Waterhouse in 1840 and were named in honour of the zoologist and artist William Swainson. Dusky antechinus can be found in two forms: a dark form and a pale form. They can be distinguished from their relatives by their much darker fur, which is also apparent in the pale form.
Dusky antechinus are found from southeastern Queensland to southwestern Victoria in Australia, and are also found in Tasmania. They are most common in mountainous regions, including Kosciuszko National Park and the Brindabella Ranges, where they are found in alpine heath or tall open forest with a dense understorey.
Dusky antechinus are entirely diurnal animals and are active at many times of the day. Adults lead a solitary life socialising only during mating and between mother and young. Dusky antechinus spend most of their active period feeding. They are not known to be territorial animals, although they have a definite home range. Dusky antechinus live in nests. They construct them from eucalypt leaves that are balled up in hollow tree trunks or in the dense understory of the forest floor. Dusky antechinus are also known for being unusually vocal for an antechinus and have been observed hissing and chattering.
Little is known about the mating habits in Dusky antechinus. It is known that competition for mates is extremely high among males. During mating, males grab the scruff of the female's neck with their teeth and the females respond by rolling, kicking, rolling, and hissing. These antechinus have a short and vigorous mating season (which occurs during winter), after which nearly all of the males die. The gestation period lasts 29-36 days. Females give birth to 6-8 young. Newborns are bright pink at birth. They begin to develop fur at 8 weeks and soon after that babies open their eyes. The young are left alone in the nest at 10 weeks and begin to eat solid food at 12 weeks. Young are completely weaned by the 14th week and are able to travel outside of the nest on their mothers back. Dusky antechinus become fully mature at around 8 months of age, near the beginning of the next breeding season.
There are no major threats to Dusky antechinus, however, local populations have been reduced by controlled burning and the instigation of pine plantations in the place of native forests. The cat and the red fox are also believed to have an impact on some populations.
The IUCN Red List and other sources do not provide the Dusky antechinus total population size, but this animal is common and widespread throughout its known range. Currently, this species is classified as Least Concern (LC) on the IUCN Red List.
Due to their diet habits, Dusky antechinus help control the populations of soil invertebrates within their range.