The purpose and main objective of the Darwin project will be to predict the invasion dynamics of an alien mammal in Argentina: the Red-Bellied Beautiful Squirrel Callosciurus erythraeus. This species was introduced to Argentina 30 years ago from East Asia. It has a wide diet, including fruits, nuts, seeds and buds, insects, and eggs of birds. In its indiginous region it is commonly kept as a pet, which is probably the origin of the introduction in Argentina. Its invasion from a single source close to Luján university in Buenos Aires province has yet to be studied, though local producers complain of losses to fruit plantations. This species of squirrel has certainly established in the local region, and shows signs of repeating the performance of numerous other invasive mammals: rabbits (introduced worldwide including to Argentina), coypus (worldwide from Argentina), grey squirrels, muskrats etc. All of these species had a slow phase of establishment typically lasting several decades, followed by very rapid expansion with devastating effects on local biodiversity. A study of the Red Bellied Beautiful Squirrel is therefore timely, before it begins an uncontrollable expansion.