When a railway was laid across Mongolia’s vast expanse, it cleaved the country in two. Constructed in the mid-20th century as a conduit through the Gobi Desert, the rail stretches from southern Russia into northeast China. But the railroad was, of course, built for humans. Which means its builders overlooked how it would affect other species, including the ungulates of the region—most notably Mongolia’s khulan. Once the track was laid, the damage was done. The khulan, a Mongolian subspecies of the onager, or Asiatic wild ass, soon vanished from the…
