North America has around 428 species of mammals. Mammal diversity in this country ranges from the tiny Least Shrew (Cryptotis parva) to the two thousand pound American Bison (Bos bison). All mammals have hair, mammary glands, and a secondary palate. Hair can be as diverse as whiskers on a cat to quills on a porcupine.

NA is home to ten orders of mammals. One of the orders, Chiroptera (the order of bats), is probably the most commonly seen mammal in North America, around 40 species make their homes here. Insect eating bats are often seen at night close to street nights when they hunt insect prey. New Braunfel's (Texas) Bracken Cave is home to more than 20 million Brazilian Free-tailed Bats, making it the world's largest colony of bats. Bat enthusiasts have even formed the Bat Conservation International organization to help and promote bats.

Smithsonian Institute's online North American Mammals is a great source to learn more about this taxon of vertebrates. Also an online version of David J. Schmidly's "The Mammals of Texas" is good resource for Texas' 172 species of mammals. For additional information regarding mammals, please visit the American Society of Mammalogists' website.