National Geographic : 1925 Sep
BATS OF THE CARLSBAD CAVERN 325 ON TIHE WING, THE GUANO BATS ARE STRONG AND SKILLFUL FLIERS (THIS SPECIMEN AND ITS QUARRY HAVE BEEN POSED BY TIHE PHOTOGRAPHER) They hunt their insect food at night, capturing and devouring beetles, moths, flies, and a host of winged insects of nocturnal habits. The guano deposited under their roosts in the caves is composed entirely of insect remains. How many insects would be required to make Ioo,ooo tons of guano? (See text, page 324.) S, Photographs by Vernon Bailey TIHE LARGE BROWN BAT, ABOUT TWO-TIIRIS NATURAL SIZE This is the commonest bat in Slaughter Canyon, near the Carlsbad Cavern, where great numbers come to drink at the water tank in the evening. In summer this bat lives mainly in the northern, forested regions of the continent, but in winter it is probable that it seeks more comfortable quarters in the south (see text, page 329). Note how the knees of a bat bend backward.