However, there is only one mammal truly adjusted to normal living inside the dark portions of the caves. This is the bat. (See illustration below). There are eight species of bats that use Oregon Caves. Most common is the long-eared myotis. None are abundant, and most visitors do not see them, for this is not a “bat cave” in the same sense as Carlsbad and other caves. Also, the bats prefer the undisturbed sections of the caves, where people seldom enter. In spite of this, they attract much interest and are the subject of much discussion. The only mammal capable of flight, bats are also unique in their ability to fly in total darkness deep within caves. [Illustration: Hibernating bat in “dry” room] This latter skill puzzled scientists for many years until, in the 1930’s, it was learned that bats navigate in darkness by echo-location, a system similar to the Navy’s sonar. The animal emits high-pitched squeaks, above the threshold of human hearing. The echo of the squeaks bounces off nearby objects and the bat is able to decipher, from a flood of up to sixty echoes a second, the size, shape, and distance of objects before them. So precise is this system that the animal is able to locate and capture flying insects in pitch darkness. Not only can they navigate in the dark, they can also remember echo patterns that help them to return again and again to the same place deep inside a cave. They feed at night, eating great numbers of insects. In winter a few of them hibernate in Oregon Caves and may be easily observed clinging head downward from the walls and ceilings for months at a time. During a bat-banding study a few years ago, 750 bats were fitted with tiny aluminum identification bands and released. To date, however, none of these bats have been found elsewhere, nor have any foreign bands turned up here. Some bats are migratory, for each year in late August or September there is an influx of several hundred that may be seen in the caves for only a few days. Then they are gone again. Certain arthropods—millepedes, spiders, moths and small wingless insects called collemboles—are abundant in the “twilight zone” of the caves, where they feed on organic matter and upon each other. Thus animal life in the cave is more prominent than many people suspect. _Plant Life_