Their tissue decomposes almost immediately, and their boneless bodies rarely fossilize. But a geological formation in Wisconsin preserved a leech fossil for 437 million years, a new study finds. It’s ...

A 437-million-year-old fossil from a deposit in Wisconsin could be the oldest species of leech ever found. By Jack Tamisiea If you look around Waukesha County in Wisconsin today, it can be difficult ...

European medicinal leeches were famous for their popular purpose: treatment for everything from cancer to mental illness. But the high demand left them endangered—still today. Bloodletting ...

There has long been anecdotal evidence of the wormy creatures taking to the air, but videos recorded in Madagascar at last prove the animals’ acrobatics. By Veronique Greenwood Veronique Greenwood ...