National Geographic : 1925 Sep
328 THE NATIONAL GEOGRAPHIC MAGAZINE .- secutive years, and other S caves have yielded comparable S amounts. A good productive bat cave has the advantage over a gold Smine in being self-perpetuating. S But the real value of the bats . lies in their enormous destruc .n tion of insect pests, which is Swell illustrated by a permanent - i yield of 60 tons a year of insect a, shells in one locality. STIHE LONG-EARED BAT STUDIED DURING HIBERNATION S Besides the vast numbers of r Free-tailed, or Guano, Bats, j 1 which hang close together under o! the roof of the highest room in Carlsbad Cavern and by their S rank odor apparently keep other m bats at a distance, there are m about a dozen species that oc S & cupy, or have occupied, various O parts of the cave or near-by .. ' caves and canyons. Of the 18 Sa2 species of bats known in New S1 ° Mexico, 13 have been found in this vicinity. o". In the farthest, deepest room oc of the cave, where there were SS 1no living bats, numerous skele , tons were found lying on the dusty floor. They were usually S old andbleached, but some were S dried mummies that may have l been there for many years. Most of these were of the .at Guano Bats, but they included . also bones of many other species. S. The Long-eared Bats, Cory 0d, norhinus rafincsqulii pallescens, o ' one of the most interesting and S - spectacular species of the region, ... a - were found in considerable num S hers in McKitterick Cave, some a- 20 miles farther north. On April 15, when first discovered, they were still in profound win ter sleep, hanging head down v from the low limestone ceiling S and on the rock walls of the cool, dry rooms, their great ears S rolled up in spiral coils like S rams' horns on each side of the .. head.