sierraclub.org - sierra magazine - sept/oct 2011 - endangered-species - on the brink: animals fighting for survival
Photography by Joel Sartore | Captions by Della Watson
The Iowa Pleistocene snail was believed to be extinct until 1972, when the Ice Age relict was discovered living in the cracks of limestone slopes in Iowa and Illinois, where cold air vents through the cracks, mimicking the Pleistocene climate. Hot air is deadly to the snails, so they cannot survive-even briefly-beyond their microhabitat. Joel Sartore explains how he captured the images without harming the fragile snails: "The entire photo set-up consisted of a flash, a macro lens, and a piece of white plastic stuck in a cracked rock. That they're the size of a pencil lead adds to the fun of trying to photograph them." (Photographed in Clayton County, Iowa)