the third premolar. The first premolar is very reduced in size compared to the other premolars. The premolars also have a distinct set of cusp on them called the posterobasal cusp. Their molars are extremely long, combine all the length of the premolar and it will barely exceed the length of the first two molars. The upper molars are narrow in size, compared to any of the other living opossums. Diet Being a member of the Didelphidae (opossums), Patagonian opossums feed mainly on insects and fruits, yet insects and fruits are fairly rare in far-southern habitats. The shortage of fruits and insects in southern regions has led the Patagonian opossum to feed on mainly birds and mice. One specimen of Patagonian opossum was caught using a dead bird as bait; this led some researchers to believe that the Patagonian opossum lives totally on birds. References Opossums Mammals of Patagonia Marsupials of Argentina Mammals described in 1921 Taxa named by Oldfield Thomas