There is no institution more adored or reviled than the modern zoo. Despite their popularity with the public, the debate over whether wild animals belong in captivity continues. Critics argue zoos traffic in living creatures, exploiting them for profit and amusement. Zoos counter they educate the public and provide refuge for vanishing species. As habitat destruction and mass extinctions accelerate, zoos may be our Noah’s Ark. But is it time to re-invent them?