Zoos are open to the public about half of the hours on a given day (or more) and for about half the time there are easily enough people in a zoo to be observing about half the animals. (If you don’t like these estimates substitute your own!)
This means that an animal on display at a zoo is under public observation about 25% of the time. Since all of them eventually die, and there are lots of zoos, there should be an animal passing to the great beyond before the eyes of visitors at least a few times a year, yet we never hear of that happening.
I can think of three reasons for this, two which should be obvious to any zoo-goer, and one that may be less obvious and which, indeed, may even be insidious.
The first reason is that we see it but don’t know we see it. Knut the Polar Bear died in a spectacular way that could not have been missed by the visitors. His death reminds me of my friend Cheryl Knott’s description of a wild male orangutan dying before her eyes (and her camera, if I recall correctly) after a protracted battle with another adult male orangutan. The animal walked out on a log overhanging a swiftly moving stream, raised both arms up over its head, and slowly fell backwards until gravity took over and splashed its suddenly lifeless body into the water. Knut the bear spun around then convulsed then did the “Oh My God I’ve Been Shot” posed like the orangutan did and fell into the water with a bit splash. But if an animal simply dies while sleeping, curled up in a ball under a fake tree next to a fake rock, the visitors would just think the animal is sleeping and its demise might not be noticed until the keepers are collecting the menagerie into their night enclosures for the evening.
Similarly (this is the second reason) many enclosures have a place where the animals can go and be out of sight, by choice. An animal may just wander off to the private place, feeling ill, and expire out of sight. A kind of local “graveyard of the [fill in kind of animal]” thing.
But I have a feeling that the third reason is the most common. When you go to a zoo, you may not be aware of the fact that for every so many animals in public view, there may be a number of animals that are not in public view, and often, these are the individuals of a given species that happen to be ill, infirm, or otherwise messed up in a way that correlates a) zoo management not wanting the public to see the creature and b) the animal being categorically closer to death than the others of its ilk. I say this is insidious but I do want to make clear what I mean. It is not insidious for zoo keepers or vets to keep ill animals in the clinic or in the hidden enclosures that most, perhaps all, zoos have. This is often for the animal’s well-being. But it is also true that such animals that don’t look right, either because they are zoo animals and for some species, zoos are not good places to live, or because of advanced age or malady. The insidious part is that zoo patrons are not allowed to see or experience the full range of conditions under which zoo animals live, or to witness the full range of conditions in which zoo animals are. The chimpanzees that spend hours a day probing their own orifices with their fists, or biting their own fur off are rarely displayed, yet many chimps or other primates who were raised in captivity may have these behaviors. Carnivores with mangy fur don’t look right, and may elicit anti-zoo feelings. And so on. The nefarious part is simply that the decision of which animals to display publicly and which ones to keep hidden would be a public relation decision made by the marketing department were it not already a decision made by the zoo’s vets and keepers.
In any event, it would be the case that animals that are kept “in the back” are also the ones most likely to die. An obvious subset of these are those that are too ill to treat and thus euthanized. That, of course, is not done in the animal’s public enclosure while the happy go lucky zoo-goers watch. Well, not in this century anyway. (Public euthanizing of zoo animals certainly had it’s day.
I suppose there is a fourth possibility: Zoo animals die in front of visitors all the time, they notice it, it gets reported, and everybody knows about this but me.