Alphadon (Greek for "first tooth"); pronounced AL-fah-don
Woodlands of North America
Late Cretaceous (70 million years ago)
Size and Weight:
About one foot long and 12 ounces
Insects, fruit and small animals
Long, prehensile tail; long hind legs
As is the case with many of the early mammals of the Mesozoic Era, Alphadon is known mainly by its teeth, which peg it as one of the earliest marsupials (the non-placental mammals represented today by Australian kangaroos and koala bears). Appearance-wise, Alphadon probably resembled a small opossum, and despite its tiny size (only about three-quarters of a pound soaking wet) it was still one of the largest mammals of its day. Befitting its small stature, it's believed that Alphadon spent most of its time in trees, well out of the way of the stomping tyrannosaurs and titanosaurs of the late Cretaceous period.