Zoos and wildlife parks are institutions that specialize in the collection and public display of wild animals, or what are described as wild animals. Many zoos and wildlife parks also display domestic animals, and some include aquariums with marine mammals and invertebrates, as well as freshwater and saltwater fish.

The Vienna Zoo, which opened to the public in 1779, is widely regarded as the oldest existing zoo in the world. The oldest “scientific” zoo (i.e., a zoo where animals were both displayed and used for scientific study) is the London Zoo, which was established in 1828 and opened to the public in 1847. The word zoo is a late-nineteenth-century popular abbreviation for the London Zoological Gardens.

It was once the case that zoos and wildlife parks were ...