A zoological garden or zoo for short, is an establishment that keeps animals on display for entertainment and scientific purposes. Several zoos were known to exist on different planets.
The Lactrans kept humans, Canopus III dinosaurs, as well as other creatures in zoos. (TAS: "The Eye of the Beholder")
Senator Letant suggested Martok that every Romulan zoo should have a pair of Klingons. (DS9: "Tears of the Prophets")
Bishop Numida kept Klingon and Romulan, among others, as prisoners in a zoo on Apailana V. They were saved through extraordinary recklessness from Federation and Klingon redshirts. (RIS Bouteina: "Take Me Out to the Zoo")
In 2378, Robert Tuff, Norman Craig, and Tracy Carson were captured by the Tealuians lead by Xojo Manjala as potential specimens for display in a zoo. (Star Trek: Pioneer: "The Caverns of Eden, Part 1, Part 2")
External link[]
Zoo article at Memory Alpha, the canon Star Trek wiki.