Some people are familiar with coyotes moving into their neighborhood or changing behaviors, but as humans interfere with ecosystems, we are starting to see the effects across the country.
The coyote is a master of adaptation, and recent studies are now revealing how these relatives of wolves and dogs have managed to succeed where many others 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. Over the past two centuries, coyotes have taken over part of the wolf's former ecological niche by preying on deer.
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 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. Yet even among such opportunists, coyotes stand out as the champions of change.
Two centuries ago, coyotes led a very different life, hunting rabbits and mice in the grasslands of the Great Plains. Smaller in size they could not compete with the much larger grey wolves. But as settlers moved west and extirpated wolf populations, coyotes were able to flourish. As the coyote populations grew so did their territories and diets.
Coyotes found themselves in the eastern US in the 40s and 50s. These eastern coyotes underwent a rapid change in their body size with some weighing as large as 35 pounds. Inbreeding was the cause of this body size change.
By examining genes biologists found these eastern coyotes exhibited geneses from wolves around the Great Lakes area. In the 1800s wolf populations were low because of human expulsion. Wolves had a hard time finding wolf mates, so they settled for coyotes.
Compared with the ancestral coyotes from the plains that we are more familiar with here in Montana, the northeastern coyote –- wolf hybrids have larger skulls and stronger jaws. These bulky coyotes can take down larger prey.
The northeastern coyotes have expanded their range five times faster than coyote populations in the southeastern US, the members of which encountered no wolves as they journeyed east.
Coyotes' ability to adapt to changes has been displayed for thousands of years. During the last Ice Age, coyotes were significantly larger than most of their modern counterparts and resembled the biggest of the present-day coyote — wolf hybrids in the northeast.
They probably scavenged meat from kills made by dire wolves and saber-toothed cats and preyed on the young of the massive ancient herbivores, such as giant ground sloths, wild camels and horses, that were abundant in North America throughout that time.
Some 13,000 years ago -- at the close of the Ice Age -- most of the megafauna became extinct due to a changing climate and Stone Age hunters. As they went, so did the largest predators, allowing the smaller grey wolves to fill the now open role. This put them in competition with the largest coyotes causing coyotes to become smaller in size. 1,000 years later coyotes had reached the same size as in most present-day populations.
Now, they're going through a whole new set of changes as they adapt to the modern landscape of North America. Genetic studies show that some coyotes are even mating with dogs, which could lead to a different sort of hybrid animal.
Researchers are struggling to keep up with the species and their impacts as they move into new regions. Unlike Montana, lots of areas have little to no wolves throughout the United State which may trigger a whole new trajectory of coyote evolution.
These new evolving coyotes will have unpredictable effects on other species in the ecosystem.