The term subfossil refers to the skeletal remains (or other evidence such as nests) of animals that are not ancient enough to be considered true fossils but can neither be considered modern. Collection agents such as predators (mammal or raptor) or pitfall traps concentrate the remains of all types of animal (mammals, reptile amphibians and birds) that lived in the surrounding community, usually in a cave or shelter where they are protected from the elements and can be preserved for thousands of years.
The collection consists entirely of Australian subfossil material covering 76 mammal species (including introduced species) and a range of birds, reptiles and frogs (mostly from barn owl pellets). The database contains 9100 records representing the remains of approximately 25,500 individuals. (Including skulls, dentaries, maxillae, etc, the actual number of specimens is much higher). The computer site records include over 600 individual collections from 300 sites or areas and 460 of these collections have been databased to date.
The collection is made up of bulk bone deposits from the floor of caves, bones excavated from sinkholes, (eg. Venus Bay and Quoll Hole on Eyre Peninsula), bones extracted from predator scats (eg. dingoes, foxes and Ghost Bats), pellets from birds of prey, particularly barn owls (both recent and pre-settlement material), and stick-nest rat nests and middens.
- Thirty specimens of a new species of extinct hopping-mouse (Notomys robustus, the Broad-cheeked Hopping-mouse) found, so far, only in the Flinders and Davenport Ranges, in South Australia. This new species has only recently been described (Mahoney, Smith and Medlin, 2008a, b).
- The remains of a recently resurrected (Medlin, 2008) extinct species, the Long-eared Mouse (Pseudomys auritus), from a cave on the Glenelg River in Victoria.
- The subfossil collection holds some of the best-preserved skulls of extinct small mammals such as the Pig-footed Bandicoot, Short-tailed and Long-tailed Hopping Mouse, Gould's Mouse, and the Lesser Stick-nest Rat, in Australia. Since many have been extracted from barn owl pellets they are stored together with their fur.
- Material extracted from the Black’s Point Sinkhole in the Venus Bay Conservation Park on Eyre Peninsula has been radiocarbon dated and offers a unique opportunity to trace the changes in the small mammal population over the last 4500 years. Remains of the thylacine were extracted from the 3030 years Before Present level of the sinkhole.
- The collection of subfossil material from Chambers Gorge in the Flinders Ranges contains the remains of 27 species of small mammal, most now extinct in the ranges. It is a time-capsule of the area before European occupation. More than 10,500 individual specimens from this area are held in the collection.