The Molossidae, or free-tailed bats, are a family of bats within the order Chiroptera. The Molossidae is the fourth-largest family of bats, containing about 110 species as of 2012. They are generally quite robust, and consist of many strong-flying forms with relatively long and narrow wings with wrinkled lips shared through their genus. Their strong flying forms allows them to fly 60 miles per hour using tail winds and at altitudes over 10,000 feet. This makes them unique among bats, as they are the only bat family that withstands the elevation. They are widespread, being found on every continent except Antarctica. They are typically found in caves, abandoned mines, or tunnels.