The Mexican fox squirrel, scientific name Sciurus nayaritensis, is a species of tree squirrel found throughout the Sierra Madre Occidental of Mexico as far south as Jalisco — and northward into the Chiricahua Mountains of southeastern Arizona, U.S.This species, or its subspecies, is sometimes called the Apache, Nayarit, or Chiricahua fox squirrel. It has been evaluated as an IUCN Red List Least Concern species.