Good Stress, Bad Stress

One of the highlights of a visit to the zoo or aquarium is the chance to see animals engaging in cool behavior.  In their natural state, many of the most exciting behaviors are driven by animals trying to procure food, or animals trying to prevent themselves from becoming food.

In the case of the former, it's often possible to redirect that energy and behavior in predatory animals towards another outlet.  Wolves, wild dogs, and cheetahs can chase ziplines.  Big cats can stalk, charge, and pounce on papier-mâché giraffes and zebras.  Carcass feeding provides a natural outlet for the actual act of consuming prey.  And for animals that prey on insects... well, it sounds harsh, but not many people care too much for the feelings of crickets.

It's trickier when the issue is animals with defensive behaviors.  Predators, after all, generally like to... well, predate.  Your dog loves to chase things.  Your cat loves to pounce.  Even in the wild, predators will play hunt, especially when they are young.  Prey animals typically only go through their defensive motions when they are upset.  That means that showing them off in a zoo setting might require putting the animal under stress, which is not something a lot of zoos would want to do.

I find horned lizards fascinating - but have never seen one shoot blood out of its eyes, one of the more unique animal defense adaptations

Of course, you could make an argument that life in the wild is stressful, and that having to sometimes display those behaviors is replicating a natural lifestyle for the animals.  Is it healthier for the animals to be able to display these behaviors from time to time?  Would it keep them from getting bored?  If a species is slated for eventual reintroduction into the wild, does it behoove the zoo to prepare them for a world in which predators and other unpleasant sources of... well... death occur?  Is there "good stress" vs "bad stress"?

I would say that there is.  The differences would be 1) how long does the stressor last and 2) is there anything that the animal can do about it, either to overcome it or to evade it?

That doesn't mean we unnecessarily startle an animal for giggles, just so guests can see a frilled lizard frill up, or an armadillo roll into a ball, or a Tennessee fainting goat faint.  Instead, it means that we should be willing to put animals in situations where they have the option of utilizing a range of their natural behaviors, with the understanding that sometimes they might react in a way that indicates some displeasure, maybe even fear or anger.  

From an educational perspective, video screens or QR codes and apps can provide a substitute for displaying some behaviors which would be too stressful or dangerous for the animal to perform (at least regularly) in a zoo setting.