Charles Simpson of Mobile, Alabama tells of meeting a young man who dives for exotic fish for aquariums. This adventurous young man said that one of the most popular aquarium fish is the shark. He explained that if you catch a small shark and confine it, it will stay at a size proportionate to the aquarium. Sharks can be six inches long yet fully matured. But if you turn them loose in the ocean, they grow to their normal length of eight feet. (1)

Mother Nature is amazing. How does the shark know that it could outgrow its surroundings, I wonder, and by what mechanism does it quit growing?

Years ago Dr. James Dobson told about an interesting experiment that was conducted with wall-eyed pike, a fish commonly found in the northern U.S and Canada. A pike was placed in a fish-tank with minnows…