The brilliantly funny Douglas Adams shares the adventures he had while writing Last Chance to See. Since he gave this talk, the Yangtze River Dolphin has been declared extinct and only 123 Kakapo remain. Komodo dragons are now listed as vulnerable, and although their population appears quite large, it was recently discovered that Komodo dragons can reproduce via parthenogenesis (which produces only males) and that there may actually be only 350 breeding females.
H/T Carl Zimmer
~Southern Fried Scientist