Every animal in this competition has its traits and armoury because of evolution, that's a null argument.
And the shark may be a killing machine, but it only kills things that are smaller than it and easy prey. How is that hard? If that's hard then we might as well start the resurgence of the...
http://www.sharkbookings.com/why-great-white-sharks-cannot-be-kept-in-captivity/
"Great White Sharks are not kept in captivity, for a multitude of reasons; critically, they do not survive."
"They get depressed in captivity. Great White Sharks that are kept within tanks have been known to head...
The Grasshopper Mouse:
It chases and repeatedly pounces at its victim until it gains a hold. It then bites through the back of the victim's skull, killing it within seconds of capture. It is known to attack other rodents THREE TIMES bigger.
And 28 acres. That's a territory the size of FOURTEEN...