nowyoukno:

As recently as the 1960s, the Angel Island mouse was reported to be abundant on at least three of the four islands it was known to inhabit. However, no specimens have been found on the islands since 1991, despite a number of surveys. The main risks to the species come from feral cats, and from introduced house mice and black rats, which compete with the endemic species for resources. The subspecies resident on the two northern islets are now listed as extinct, while the entire population on the southern islet of Estanque was probably driven to extinction by a single cat, present on the island only between 1998 and 1999.

The species is currently listed as critically endangered by the IUCN, but since no living specimens have been seen for twenty years, as of 2011, it may well be entirely extinct. It has been estimated that, if the species still survives, it is likely restricted to an area of no more than 10 square kilometres (3.9 sq mi)