Although humans go to zoos to look at animals,

Although humans go to zoos to look at animals, they do not generally see far beyond outward appearance and behavior. When a look is exchanged between human and animal that reveals too much, boundaries can melt away. When moats began to replace bars in zoos across Europe, and then around the world, a compromise was born that humans could handle. Hagenbeck’s ideas offered zoo-goers reprieve from unwittingly doubting their own self-identity while gazing into expressive eyes with emotions resembling their own. Humans no longer had cause to believe the story that those sad eyes staring out at them were emitting; the animals’ voices, according to Rothfels, were finally silent. These radical changes in the representation of animals in zoos convinced many humans that animals in zoos were happy or content in their forged habitat. http://www.carnivoreconservation.org/files/thesis/malcom_2005_msc.pdf