Predator and Prey

I've heard this theory / story before. I feel like I'm in that situation now.

Aquarium fishes are air flown from country to country. However, due to some unknown reasons, the fishes died in a perfectly healthy, predator-free environment. Scientist did some research and tried to introduce various external factors into the environment to improve the survivability of the fishes.

Guess what?

The presence of a predator actually increased the number of fishes that survived. The possible explanation is that the fishes had to "fight" for survival and hence they did better than just nothing. Maybe we all do. When the impeding deadline is approaching, we can push our bodies to its limit, we can focus on the task at hand. When we're given the will and time to relax, we slack.

We're not so different from fishes after all.