Alphadon is thought to have been a small mouse-like mammal with a prehensile tail and feet adapted for climbing trees.
Alphadon lived in Late Cretaceous North America just as flowering plants were beginning to transform the landscape. They lived in an environment of rivers, deltas and marshes.
Alphadon, which lived a nocturnal lifestyle up in the trees, might have had excellent hearing.
Alphadon had a generalised dental pattern allowing it to feed on a variety of different foodstuffs including plants, insects and small vertebrates.
Alphadon probably had an excellent sense of smell, which would have allowed it to track down food during the dead of night.
Alphadon was first discovered by George Gaylord Simpson in 1929 when he uncovered the teeth of this early marsupial. The teeth, along with the isolated jaw and skull fragments, remain the only fossils of Alphadon. As a result, much of its biology is inferred from its closest living relative, the opossum. Perhaps one day we will be lucky enough to find an entire or partial skeleton of Alphadon, which would give us a better idea of the evolution of these early marsupials.
Height: 0.05m (0.16ft)
Length: 0.3m (0.98ft)
Weight: 0.1kg (0.21lbs)
Top speed: 6.5kph (4.03mph)
Vision: Alphadon probably had excellent binocular vision for a life hunting and foraging in the trees.
Skin: Alphadon was a mammal and would have been covered in fur to help maintain a constant body temperature, just like mammals today.
Brain: Didelphid marsupials today have the smallest brains of all mammals and Alphadon would probably have been the same. Despite its lack of brain power, it was still more intelligent than many dinosaurs!
Prey: Alphadon was omnivorous, feeding on fruits, invertebrates and possibly the small vertebrates of the Late Cretaceous.
Bite: Alphadon teeth had high and sharp cusps, well adapted for piercing and perfect for crushing the hard shells of insects.
Nest: Based on comparison with its living relative, the opossum, Alphadon might have given birth after just 14 days of gestation to a single tiny joey. At just a tenth the weight of a paper clip, the joey would attach itself to its mother's teat until it was old enough to venture out on its own.