This crab could save your life - if humans don't wipe it out first

The Horseshoe crab outlived the dinosaurs but is no match for medicine's hunger for its blood

Few people in the world are aware their wellbeing may one day depend on a blue-blooded crab that looks like a cross between the facehugger from Alien and a gigantic louse. Fewer still realise this ancient creature now faces its greatest threat in more than 450m years.

The American horseshoe crab outlived the dinosaurs and has survived four previous mass extinctions, but is now menaced by the pharmaceutical industry, fishing communities, habitat loss, climate change and, most recently, choking tides of red algae off the east coast of the United States.