Sadly, this happens all too often. As National Geographic points out, 42 animals have died during escapes or attacks in US zoos since 1990. During that time, 15 humans have been killed at zoos, and 100 have been injured. Of these injuries, only 15 incidents involved primates. The last time a gorilla was fatally shot in a US zoo was in 2004, when 13-year-old Jabari was killed after escaping from the Dallas Zoo.

There’s a strong case to be made that zoo officials made the right decision by killing the ape. After all, it wasn’t clear whether or not the gorilla would continue to harm the boy, and tranquilizers would’ve taken too long to sedate the animal.

The public is upset that the zoo shot a beloved 17-year-old Western lowland gorilla (a threatened species of which fewer than 175,000 still remain in the wild); the police are worried that the parents dared to take their eyes off a three-year-old for a split second; and activists are concerned that the zoo isn’t safe for animals or humans. In other words, people are pointing fingers in every direction.

Because a gorilla was shot and killed after escaping from an “award-winning” exhibit at the Dallas Zoo.

Because this giraffe was killed and fed to lions when he had outlived his “usefulness.” (NSFW)

penguins are on anti-depressants.

If the motivation of zoo owners was truly to inspire passion for conservation then, with a little imagination, they could begin to lead the way out of this archaic practice and towards a learning experience which was both valuable and, most importantly, free of suffering.

I can say with great confidence that a zoo enclosure can never be a proper substitute for an animal's natural habitat.

I think the overriding point here is that, even if they did inspire a passion for conservation, the end does not justify the means.

Many of the smaller zoos are exempt from the licensing standards and thus, are not subject to inspections. For the larger zoos, they are inspected once a year (at best) or once every three years (as a minimum). The inspection is carried out over a maximum of two working days and might have to assess hundreds or even thousands of animals. When you bear in mind that the inspectors also need to review record keeping, health and safety, procedures, education and conservation contribution in the allotted time, it becomes clear that, even with the best of intentions, the system is simply unworkable.

I agree that there are "worse zoos" but I do not believe that there is such thing as a "good zoo".

Worryingly, zoos teach children that humans can control nature. They demonstrate that if an irreplaceable natural habitat is destroyed by our actions, we can pluck individual animals out of the destruction, manipulate their breeding cycle and produce more of them to live in city centre zoos or safari parks thereby "saving" the species

What it fails to demonstrate to the child [is] the urgency of the need for habitat conservation, or the complexity of the role of the tiger in its natural habitat, or the ways in which that child could aid the conservation of the species in reality.

By showing a tiger in a cage to a child, a zoo can teach that child nothing more than the size of a tiger, the colour of a tiger and the shape of a tiger. A zoo shows the animal completely out of context, outside of its natural habitat and the ecosystem it was designed to inhabit.

"Disorders like phobias, depression and OCD, documented at zoos, don’t appear to have analogues among animals living in the wild."

So much confinement and artifice is bound to drive the animals crazy, Wallace-Wells argues, even if they've never known anything else.

the cushy lives of zoo animals have made them a bit soft. "An animal in the wild can’t afford to be depressed," she says in the Times piece. "It will simply be killed or starve, since its environment requires constant vigilance."