The International Union for the Conservation of Nature (IUCN) lists 26 bat species as Critically Endangered, meaning they face an imminent risk of extinction. Fifty-one others are Endangered, and 954 bat species are considered Vulnerable. Bats also are among the most under-studied of mammals. The IUCN lists 203 bat species as “Data Deficient”– there is simply too little information available to determine their conservation status, and over 150 newly described species have yet to be added to the IUCN Red List and have yet to be formally assessed.