Wolf In Coyote's Clothing
The coyote, also known as the American jackal or the prairie wolf, is a canine predator found throughout North and Central America. Ranging from Panama in the south, north through Mexico, the United States and into Canada the wily Canis latrans has been spreading into new territory in the Eastern US, filling a void left at the top of the food chain by the virtual extinction of the gray wolf. But these new coyotes are not the little dog sized creatures from the South West—the new coyote is larger, stronger and more aggressive than his ancestors. Well known as a master of adaptation, new studies over the past few years are now revealing how these relatives of wolves and dogs are evolving into a new top predator thanks to humans. They have expanded their diet to include squirrels, household pets and even deer. Supposedly, coyotes killed a 19-year-old female hiker in Nova Scotia in 2009. It seems that this new breed of predator is actually a wolf in coyote's clothing.
Ecologists and green organizations frequently bemoan the extinction of various species at the hands of man. Some go so far as to declare a human caused “6th mass extinction,” sometimes refered to as the Anthropocene epoch. What is seldom mentioned is that some species have been helped by human activity: rats, termites, and kudzu come to mind. Recently, the mostly ignored coyote has been in the news for its rapid spread into new areas. In a news feature in Nature, “Rise of the coyote: The new top dog,” Sharon Levy describes the coyote's success:
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 westward expansion of settlers in the 1800s and early 1900s led directly to the near extinction of indigenous large predators: lynx, mountain lions and, in particular, wolves. Coyotes thrived because they bred more quickly than wolves and had a more varied diet. Since then they have spread throughout the contiguous 48 mainland United States, most of Mexico, and large parts of southern Canada. See the Map below.
Coyotes are not the only mid-sized predators that have taken advantage of humans wiping out larger local carnivores. Reportedly, in sub-Saharan Africa, intense hunting of lions and leopards has led to a population explosion of olive baboons. The baboons are now preying on smaller primates and antelope, causing a steep decline in their numbers. This illustrates a simple fact of nature that is often overlooked in the rush to blame humans for wiping out large predators around the world: nature leaves no ecological niche unfilled for long. In other words, you wipe out one top predator and another species will soon adapt and fill the missing predator's position in the food chain.
This is not to say that humans should feel free to wipe out species with abandon—every species represents nature's handiwork over the ages and should not be cast aside lightly. Each species is unique and should be studied by scientists. Besides, trading old predators for newly evolved ones may not be the best idea. For example, the new coyotes are much bigger and stronger than their western cousins. A report, “Rapid adaptive evolution of northeastern coyotes via hybridization with wolves,” by R. Kays, A. Curtis and J.J. Kirchman, in Biology Letters tells why:
The dramatic expansion of the geographical range of coyotes over the last 90 years is partly explained by changes to the landscape and local extinctions of wolves, but hybridization may also have facilitated their movement. We present mtDNA sequence data from 686 eastern coyotes and measurements of 196 skulls related to their two-front colonization pattern. We find evidence for hybridization with Great Lakes wolves only along the northern front, which is correlated with larger skull size, increased sexual dimorphism and a five times faster colonization rate than the southern front. Northeastern haplotype diversity is low, suggesting that this population was founded by very few females moving across the Saint Lawrence River. This northern front then spread south and west, eventually coming in contact with an expanding front of non-hybrid coyotes in western New York and Pennsylvania. We suggest that hybridization with wolves in Canada introduced adaptive variation that contributed to larger size, which in turn allowed eastern coyotes to better hunt deer, allowing a more rapid colonization of new areas than coyotes without introgressed wolf genes. Thus, hybridization is a conduit by which genetic variation from an extirpated species has been reintroduced into northeastern USA, enabling northeastern coyotes to occupy a portion of the niche left vacant by wolves.
Kays et al. studied the extent of hybridization undergone by various coyote populations within the expansion zone and found a number of competing populations. “Northeastern coyote skulls are not simply larger versions of their western relatives, but show additional craniodental characteristics similar to wolves, supporting the hypothesis of the introgression of genetic variation; northeastern skulls are proportionally broader, with greater areas of attachment for masticatory musculature,” they explain. In large-prey hunters, such as wolves, there are similar traits, traits associated with strong biting forces and the mechanical stresses imposed by large, struggling prey.
Mitochondrial haplotype frequencies of eastern coyotes
The map above, taken from the Biology Letters paper shows the type and extent of hybridization. Note that GLW stands for Great Lakes Wolf, a distinct wolf linage originating around Ontario. What we see here is not just the spread of a species from one territory to another, it is the creation of a new species. “We need to stop looking at these animals as static entities,” says mammalogist Kays. “They're evolving.”
That is the message behind the rise of the new “super” coyote: animal species are not fixed, immutable things that have always existed as they are today and cannot evolve into other forms. Nature is always changing and the inhabitants of the natural world are constantly changing with it. When humans change nature, the organisms affected can change in response, just as the coyote is changing. Nature is not like a china shop, filled with fragile static objects that can be only admired or broken. Many creatures—indeed, the most successful creatures—have the innate ability to adapt to a changing environment.
Consider the coyote when you next hear an ecologist or green activist bemoaning mankind's wholesale slaughter of Earth's species. Many species will die out in the course of time without a push from H. sapiens, others will be forced to evolve. Those that have overspecialized and cannot change quickly enough will go extinct—that is natures way. Recall that, as we stated in The Resilient Earth, it has been estimated that 99.9% of all species that have ever lived on Earth are now extinct (see “Nature, Cruel and Uncaring”). Humanity, as apex predator, is simply acting out the role nature has decreed. Still, eco-activists, assured by their own ignorance, continued to spew lies and half truths about humanity ravaging nature. Perhaps someday in the future they will be devoured by a pack of highly evolved coyotes. Then, indeed, man will be the coyote's best friend.
Be safe, enjoy the interglacial and stay skeptical.