The Karner blue butterfly (Lycaeides melissa samuelis) was federally listed as endangered in 1992. This postage stamp-sized butterfly was once commonly seen from eastern Minnesota to Maine, but has severely declined in recent decades due to widespread habitat loss. It is specialized to live in pine and oak savannas or similar open dry sandy prairies. Adult Karners sip nectar at a variety of flowers, but their caterpillars feed only on wild lupine (Lupinus perennis). Amazingly, the caterpillars produce a sugary liquid from glands to attract hungry ants that in turn protect the caterpillars from parasites and predators. In 1998, following six years of habitat restoration at the Kitty Todd Nature Preserve in northeast Ohio, the Toledo Zoo and several conservation partners successfully re-introduced Karner blues into their former range. The Cincinnati Zoo is now helping to support this important project by studying the ant-caterpillar relationships at Kitty Todd and other possible future re-introduction sites.