Their ears are formed to maximize hearing, as well as contribute to lift during flight. Long, narrow wings are geared for high speed and maneuverability. The bones in a bat's wings are like the bones in your arm and hand. The wing is formed by two thin layers of rubbery skin stretched out between these fingers. From birth, bats have a 50 percent chance of survival during the first year of life.
Males reach sexual maturity around their second year.
Females as young as a year have been found pregnant. Mexican free-tails are so called because at least a third of the tail protrudes beyond the membrane that connects the leg and tail. Prominent wrinkled lips help direct sounds needed for navigation. Short, velvety fur helps reduce drag. Bat droppings, called guano, are one of the richest fertilizers.