The Evolution Of Coyotes

Scientific American:

Researchers have long known the coyote as a master of adaptation, but studies over the past few years are now revealing how these unimposing relatives of wolves and dogs have managed to succeed where many other creatures have suffered. Coyotes have flourished in part by exploiting the changes that people have made to the environment, and their opportunism goes back thousands of years. In the past two centuries, coyotes have taken over part of the wolf's former ecological niche by preying on deer and even on an endangered group of caribou. Genetic studies reveal that the coyotes of northeastern America — which are bigger than their cousins elsewhere — carry wolf genes that their ancestors picked up through interbreeding. This lupine inheritance has given northeastern coyotes the ability to bring down adult deer — a feat seldom attempted by the smaller coyotes of the west.
The lessons learned from coyotes can help researchers to understand how other mid-sized predators respond when larger carnivores are wiped out. In sub-Saharan Africa, for example, intense hunting of lions and leopards has led to a population explosion of olive baboons, which are now preying on smaller primates and antelope, causing a steep decline in their numbers.
Yet even among such opportunists, coyotes stand out as the champions of change. “We need to stop looking at these animals as static entities,” says mammalogist Roland Kays of the North Carolina Museum of Natural Sciences in Raleigh. “They're evolving”.
At a fast rate, too. Two centuries ago, coyotes led a very different life, hunting rabbits, mice and insects in the grasslands of the Great Plains. Weighing only 10 to 12 kilograms on average, they could not compete in the forests with the much larger grey wolves (Canis lupus), which are quick to dispatch coyotes that try to scavenge their kills.

They are definitely pretty damn smart.  I tried to run one over with a snowmobile, but every time I got close, he'd turn in a tighter radius than I could and get some space on me.  I've decided that so long as they kill cats and groundhogs, don't kill my calves and don't kill too many chickens, I'll only take the occasional shot at them.  Of course, that's because I only occasionally see them.