The southern bent-wing bat (Miniopterus orianae bassanii ) is one of two subspecies of the Australasian bent-wing bat. Its population size has declined rapidly since the 1950s, and it is classified as critically endangered by the Australian government.
The subspecies name is derived from the border between this subspecies and the eastern bent-wing bat, the Bassian volcanic plains.
The southern bent-wing bat is slightly larger than the other two subspecies of bent-wing bats in Australia. It has an average weight of 15.7g and average forearm length of 47.6mm.It roosts in caves and rock crevices. Its range is restricted to southeastern South Australia and southwestern Victoria.Their lifespans can be at least 20 years, as determined by the recapture of banded bats.
Mating occurs in the autumn, but the embryo doesn't begin to grow until the spring due to delayed implantation.Females do not reproduce until their second year.The offspring, called pups, are born at 20% of their adult size, and reach full size by ten weeks of age.Southern bent-wing bats rely heavily on cave structure, choosing caves that allow high heat and humidity, which promotes development of their young, which are born hairless.The pups begin learning to fly at seven weeks old.
The southern bent-wing bat is one of only five mammals in Australia to have the designation critically endangered; listing occurred in 2007. During the summer breeding season, most of the species now forms maternity colonies in two caves, Bat Cave in Naracoorte Caves National Park and Starlight Cave in Warrnambool. The Naracoorte site hosted up to 200,000 individuals in the 1950s and 1960s, but in 2009, there were an estimated 20,000 individuals. An immense breeding colony once existed at the Widderin caces near Skipton, as the Chief Protector of Aborigines in Victoria, George Augustus Robinson, discovered in the mid 1840s. That habitat ceased to function as a colony by the late 1860s.
