Due to centuries of myth and superstition, bats are among the world's least appreciated and most endangered mammals. Losses are occurring at alarming rates worldwide. The causes of their decline include vandalism, commercialization of caves, insecticide poisoning and loss of prey, loss of habitat, especially roosting sites, and the capture for laboratory use. Bats are exceptionally vulnerable to extinction, partly due to the slow reproduction rate, most producing only one young annually.
Nearly 1,000 species of bats account for almost a quarter of all mammal species.
Tropical bats are key elements in rain forest ecosystems which rely on them to pollinate flowers and disperse seeds for countless trees and shrubs. Important agricultural plants, from bananas, breadfruit and mangoes to cashews, dates and figs, rely on bats for pollination and seed dispersal.
In Britain there are fourteen species of bat, all of which are found on the south coast of England, only seven or eight in the middle of England and two or three in the north of Scotland. This variation is due to the greater availability of insects to feed on in the south, with its warmer climate and different farming methods; and possibly a greater number of roost sites.
More than 50% of American bat species are in severe decline or already listed as endangered. Endangered species of Chiroptera in the USA include the Indiana bat, Hawaiian hoary bat, ozark big-eared bat, Virginia big-eared bat, and the spotted bat.
White‐nose syndrome has recently decimated bat populations across North America. The fungal disease (Pseudogymnoascus destructans) was first detected in the United States in 2006 at a popular tourist cave in the state of New York. Since then, the disease has spread across North America, killing millions of bats in its wake, with many local populations experiencing 90 to 100% mortality, probably due to their naive immune systems (In Europe and Asia, where P. destructans is endemic and widespread, few bats exhibit white-nose syndrome and mortalities are rare.) The fungal pathogen is cold-loving, ceasing to grow at temperatures above 20°C. The only time it can infect and kill bats is when they hibernate. There is concern that the fungus will eventually reach other parts of the world, such as Australia, and worsen the extinction-bound trajectory of several cave-roosting species, most notably the eastern and southern bent-winged bats.