Mammals in U.S. zoos

Mammals are what most people picture when they picture a zoo, and they dominate the acreage at almost every American collection — big cats, primates, hoofstock and bears take up the flagship exhibits and most of the signage. That weighting is partly about visitor expectation and partly about what a temperate-climate institution can house outdoors year-round. The interesting variation between zoos is less about which mammals they hold than about how much room they give them, and whether the collection extends past the charismatic set into the small, nocturnal and unglamorous species that are harder to build a crowd around.