ExtinctionIt is unknown why Fitaweskus became extinct in the Late Pliocene. It is possible that they died out because of the climate change causing the Ice Age, but as recent evidence shows, climate change likely didn't effect their populations during that time. Newer fossils suggests that it is more likely that competition from some newer predators like mustlid-group mammals (black-footed ferrets, weasels, etc) drove the Fitaweskus to extinction.
De-Extinction and reintroduction plans
In 2014, a group of Japanese scientists have brought this animal back through De-Extinction with no negative side effects, unlike the failed plan to bring the Pyrenean ibex back, using a domestic meerkat as a surrogate mother. These resurrected fitaweskuses are now a very common household pets in North America alone, about as common as house cats. There has been a lot of talk whether the resurrected Fitaweskuses would have positive impact or negative impact (competing with the now-native weasels, black-footed ferrets, ect) remains questionable.