Since the first human settlements circa 4000 B.P., all available data suggest that the terrestrial mammal fauna of the French West Indies was totally replaced, bats taken apart. All endemic species are currently extinct, and the eight species currently present have been introduced, one during the pre-Colombian period, six during the colonial period, and the last recently. The alien status given to several species that were previously considered as endemic or native drives to the recommendation to reconsider regulations and official pictures of these species. The last introduced species is a squirrel we identified as Funambulus pennantii. A pair from a Florida pet shop was introduced during 1968 in an islet of the Guadeloupe southern cul-de-sac where it founded a small feral population. Thereafter, some individuals from this Population were introduced in a Pointe-a-Pitre suburb hill, from which the species colonized or was introduced on several other hills. We hypothesize the invasive risk of this squirrel in the climatic and ecological context of Guadeloupe, starting from an investigation of biological and ecological traits of the species in its original distribution area, the North of the Indian subcontinent.