These images were taken at a time when zoos obtained their animals from the wild and as gifts from wealthy collectors. Modern veterinary medicine was in its infancy and even so, the medical needs of these wild animals were poorly understood. Cleanliness was emphasized, thus barren enclosures often with concrete floors were used. Unlike modern zoos, social needs and environmental enrichment were not considerations. And at some zoos, the animals were exploited for entertainment.
The Ethical Evolution of Zoos looks at the history of displaying wild animals, the individuals who influenced change (including an animal dealer who exhibited human beings) and the development of immersion exhibits where visitors could feel as if they were observing animals in the wild.
An opinion piece on zoos written in the aftermath of the killing of Harambe the gorilla in Cincinnati, 2016.
Conservation, education and research efforts provided by zoos have been financially undermined because of pandemic restrictions.