The Delmarva fox squirrel may look like a typical backyard squirrel, but it's not: it's larger than the common gray squirrel and has been listed as an endangered species since 1967. According to the U.S. Fish and Wildlife Service, it was once found throughout the Delmarva Peninsula, southeastern Pennsylvania and southern New Jersey, but habitat loss and fragmentation from development has decreased its range by 90 percent. That means wildlife refuges like Blackwater are one of the few safe havens for this species.
Photo by Larry Meade/USFWS Headquarters, Flickr