Carlsbad Cavern is one of more than 300 limestone caves in a fossil reef formed 250 to 280 million years ago. American Indians lived in the Guadalupe Mountains 14,000 years ago, where the caverns are located. The park still has cooking rings and pictographs from those tribes. It's not known who actually set foot in the caverns first, but cowhand Jim White is credited with being the first to explore them extensively in 1898. Amelia Earhart visited the bat caves in 1928. In 1962, "Journey to the Center of the Earth" was filmed in the caverns.
Before 1925, visitors entered the bat cave from the cave's natural entrance using a guano mining bucket. Visitors stood atop the bucket and were hoisted down into the cave. The caverns' first elevator was installed in 1932. The 750-foot shaft was created by drilling holes at the cave's entrance and from inside the cavern. Two larger elevators and a second shaft were added during the 1950s. In most tours, visitors walk through the caverns, but some specialized tours require crawling through tight spaces.
The bats' exit flight lasts between 20 minutes and two hours and usually begins just before sunset. They may travel in a thick cluster or a long, thin, barely visible stream. They initially fly out in a swirling funnel to lift up into flight. Researchers have taken infrared photos of the bats sleeping during the day in an attempt to count them. An estimated 250 to 300 bats per square foot roost on the walls and ceilings, but this changes depending on the season. In 2005, Dr. Thomas Kunz and Dr. Nickolay Hristov of Boston University counted 400,000 bats flying from the bat cave using a camera sensitive to temperature variation.
Fifteen different species of bats inhabit Carlsbad Caverns. Most are Mexican free-tailed bats. The bats have red, brown or gray fur. Their ears point forward and their lips are wrinkled. While other bats have tails completely enclosed in their membranes, Mexican free-tailed bats have tails that extend beyond the membrane. Though these bats prefer caves, they also live under bridges or in abandoned buildings. They eat insects, so they roost near water where insects are attracted. These bats are very fast flyers, and they can live up to 18 years.
