The Driftless Area National Wildlife Refuge is home to Discus macclintocki, a species of land snail in the family Discidae, known commonly as the Iowa Pleistocene snail and Pleistocene disc. It is about 5 millimeters in diameter.
The Iowa Pleistocene snail was thought to be extinct until it was discovered in 1955 by a scientist working in northeastern Iowa. It was listed as endangered by the United States in 1978. The main cause of the snail's decline is climate change, as it is restricted to patches of cold habitat in warmer surroundings. The snail is considered a to be a relic of the ice age. About 75% of this snail’s original habitat has been destroyed since 1850. Other causes include loss of habitat to logging, quarrying, livestock, pesticides, the construction of roads, and predation by shrews.
The International Union for Conservation of Nature assessed the snail as a species of least concern for the Red List, because its subpopulations are apparently stable and none were lost in the decade prior to the assessment. However it is a federally listed endangered species.