are incredibly common throughout the world. They probably outnumber all other animals in total numbers. There are over 850 known species of bats, and they are second only to rodents
in number of species. Every continent in the world has bats, with the exception of Antarctica
, and some of the species have existed in their present form for over 50 million years. The vast majority of bats live in tropical regions, with only 44 species known to exist in North America
. Bats belong to the mammalian order Chiroptera
, meaning "hand-wing".
Adult bats in North America range in size from less than a tenth of an ounce and having a wing span of 4 inches to weighing over 2.2 pounds and having a wing span of 6 feet. Most bats eat insects, although some eat fruit, vegetation, and even rarely frogs, small rodents and blood. Bats are incredibly important in controlling insect populations. One bat can eat an amazing 1000 to 3000 mosquitos in a single night. Because of this, many people are now putting bat nesting boxes in their yards, or planting bat gardens, with plants designed to attract bats. Bat watching is becoming a popular form of eco-tourism. Wildlife viewers from around the world visit Bracken Cave in Texas to watch over 20 million free-tailed bats rise in huge columns at dusk in pursuit of over 250,000 pounds of insects each night. One cave in Texas, the Eckert James River Bat Cave houses an incredible eight million bats each summer. This particular cave is a maternity colony where female nest before returning to Mexico for the winter.