From 1880 through 1932, the Orient Mine was the largest producer of iron ore in Colorado. When the iron mine permanently closed in 1932 people began to leave the once-booming town. But in 1967, a new breed of residents was discovered to be living in the abandoned area - thousands of Brazilian Free-Tail Bats.

An estimated 250,000 bats make up the Orient Mine Bat colony, making it the largest in Colorado, and one of the biggest colonies in America.

The bats roosting in the mine are mainly made up of males, which is often referred to as a 'bachelor colony.' The males congregate and spend the summer in Colorado and migrate to Mexico, Central America, and South America during the winter. In addition to the Brazilian Free-Tail Bats, several other species of bats live in the cave all year round.

Colorado Parks and Wildlife monitors the bats' behaviors and activity with special detectors that are placed throughout the mine. Occasionally, the Brazilian Free-Tail Bats bats are swabbed by biologists to gather samples and data regarding the species. The Orient Mine is a designated Colorado Natural Area and Colorado Division of Wildlife Watchable Wildlife site.

The bats emerge at dusk, and ribbons of these elusive mammals with eight-inch wing spans can be seen swooping through the sky at speeds of up to 60 miles per hour.

The Orient Mine bat colony is one of the San Luis Valley's most important resources. The animals control insects by eating them, which also results in fewer pesticides having to be used on crops in the region. Another perk is that they help to keep away mosquitoes from the nearby hot springs.

Orient Land Trust manages the historic area in San Luis Valley. Visitors can take a trail to the cave and watch the nightly phenomenon at 64393 County Road GG, in Moffat, Colorado.

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