Pets are not allowed in the amphitheater area. Fringed Myotis Nearly 1,000 feet below the surface, and over a mile from any known opening, lives a colony of about 100 Fringed myotis bats. This maternity colony roosts just above Lake of the Clouds, the lowest and warmest point in Carlsbad Cavern. This opening, located 200 yards east of the main cave entrance, is surrounded by a fence. It was also found that lights left on in the cave delayed the emergence of the Fringed myotis bats.
Rangers now turn out all lights in the cave at the end of each day.
The colony of Mexican free-tailed bats at Carlsbad Cavern declined from an estimated 8.7 million in 1936 to approximately 200,000 in 1973. Similar declines have been noted throughout the southwestern United States and Mexico. The pesticide DDT is thought to be the primary cause. In 1996 infrared photographs were taken of the ceiling in the Bat Cave of Carlsbad Caverns. The population nearly doubled to an estimated 352,000 bats by fall when the young were flying.