Here’s another cool story about how nature keeps itself in check! Over ten years ago, wildlife biologists (scientists who study animals and plants in the wild) gathered up wolves from around North America and returned them to Yellowstone Park in Wyoming. There had been no wolves in the park for over 70 years. Of course, the elk that live there weren’t too pleased about the whole affair. After all, they had been living in the park for years, growing in number because there was no longer a natural enemy that hunted them. Why were there no wolves in the park for over 70 years? Humans had hunted them all! As result, the number of elk grew so large that they were pretty much eating up all the young aspen tree shoots in the park, their favorite treat! Without the wolves to keep the number of elk under control, the aspen suffered! In fact, the situation was so bad that there were almost no aspen trees left!

But in 1995, the wolves returned to the park and over time, the number of elk fell again. And as a result, today, the aspen trees have recovered! This is how nature keeps the number of organisms in an area balanced! Many people are afraid of wolves, and hunt them down to protect their farm animals, or even for sport. But wolves too have an important role to play in nature, just like all other creatures. Without them, and other large predators (animals that eat other animals), nature would soon be out of whack!