A pair of little brown bats zig-zagged above our farm last evening, feasting on mosquitos, moths and other flying insects. Locating their prey by high-frequency sonar (echolocation), bats capture small insects directly in their mouth but use their wing membranes to snare larger victims. Contrary to popular folklore, bats are also equipped with good visual acuity.
Bats evolved early in the Cenozoic Era, just after the demise of the dinosaurs. The forelimbs of their terrestrial ancestors developed into webbed digits and thence into membranous wings while the hindlegs retracted into short, clawed appendages. Today, more than 920 species of bat inhabit our planet, representing 20% of all mammals. Large, fruit eating bats, often called "flying foxes," are found throughout the tropics, as are the infamous vampires; most bat species are relatively small insectivores.
Bats of the Temperate Zone hibernate through the winter, using caves or attics. Though most of these species breed in the fall, fertilization is delayed until early spring and females gather in nurseries by May or June; the latter may be in caves, tree cavities or abandoned buildings. Males often remain solitary through the summer but may gather in small groups. Unreasonably feared, bats play an important part in the control of insect populations and are surely more welcome in the neighborhood than those noisy insect zappers; on the other hand, bats can carry rabies and should not be handled.
