How Leeches Can Track Down The World's Rarest Animals
Blood Bank Leeches can store blood while taking months off between meals. Simon Mahood/WWFPlus: zoology's most wanted. THE PROBLEM Many animals are still almost complete mysteries to science. According to the International Union for Conservation of Nature, researchers don't know enough about 15 percent of mammals to even determine whether they're threatened by extinction. Researchers try to track them using footprints, dung, and motion-sensitive cameras, but it's difficult work, particularly in dense rainforests. Take the saola, nicknamed the Asian unicorn, a deerlike animal with two straight horns. Researchers first saw its horns in hunters' homes in 1992; since then, they've found remains in the forest, but no scientist has spotted one in the wild. THE SOLUTION Tom Gilbert, a geneticist at the University of Copenhagen, has found that leeches are a great way to track down rare creatures. He was inspired after a colleague monitoring rare tapirs in Malaysia was bitten by a...