Carlsbad Caverns National Park in New Mexico_美文

Carlsbad Caverns National Park in New Mexico

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BARBARA KLEIN: People are not the only ones who visit Carlsbad Caverns National Park. About four hundred thousand Mexican free-tailed bats come to the big cave from Mexico each summer to give birth.

Every evening, as the sun goes down, thousands of adult bats fly out of the natural entrance of the cave. It can take from twenty minutes to more than two hours for them all to leave. The bats fly to nearby river valleys to feed on night-flying insects. Then, toward morning, they return to the bat cave within Carlsbad Cavern.

Park Service rangers explain that mother bats find their babies by remembering their location, their smell and the sound of their cry. Mothers and pups hang in groups on the ceiling. They spend the day resting and feeding.

While the adults go out at night for food, the young bats hang out in the cave for four or five weeks. Then, in July or August, they join their mothers on these nightly flights.

Finally, in late October or early November, the bats all leave and return to Mexico. But they always return the next year.

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BOB DOUGHTY: It is easy to imagine that it was the bats that led ancient people to discover the cave. Archeologists and others have found evidence of Ice Age hunters near the cave entrance. They have also found pieces of spear points left about ten thousand years ago.