Passage 2

Like some people who might rather not admit it, wolves faced with a scarcity of potential sexual partners are not beneath lowering their standards. It was desperation of this sort, biologists reckon, that led dwindling wolf populations in southern Ontario to begin, a century or two ago, breeding widely with dogs and coyotes.

Interbreeding between animal species usually leads to offspring less vigorous than either parent--if they survive at all. But the combination of wolf, coyote and dog DNA that resulted from this reproductive necessity generated an exception. The consequence has been booming numbers of an extraordinarily fit new animal spreading through the eastern part of North America. Some call this creature the eastern coyote. Others, though, have dubbed it the "coywolf".

The animal‘s range has encompassed America‘s entire north-east, urban areas included, for at least a decade, and is continuing to expand in the south-east following coywolves‘ arrival there half a century ago. This is astonishing. Purebred coyotes never managed to establish themselves east of the prairies. Wolves were killed off in eastern forests long ago. But by combining their DNA, the two have given rise to an animal that is able to spread into a vast and otherwise uninhabitable territory. Indeed, coywolves are now living even in large cities, like Boston, Washington and New York.

Some speculate that this adaptability to city life is because coywolves‘ dog DNA has made them more tolerant of people and noise, perhaps counteracting the genetic material from wolves--an animal that dislikes humans. And interbreeding may have helped coywolves urbanize in another way, too, by broadening the animals‘ diet. Having versatile tastes is handy for city living. Coywolves eat pumpkins, watermelons and other garden produce, as well as discarded food. They also eat rodents and other smallish mammals. Many lawns and parks are kept clear of thick underbrush, so catching squirrels and pets is easy. Cats are typically eaten skull and all, with clues left only in the droppings.

Thanks to this bounty, an urban coywolf need occupy only half the territory it would require in the countryside. And getting into town is easy. Railways provide corridors that make the trip simple for animals as well as people.

Surviving once there, though, requires a low profile. As well as having small territories, coywolves have adjusted to city life by becoming nocturnal. They have also learned the Highway Code, looking both ways before they cross a road.

Whether the coywolf actually has evolved into a distinct species is debated. Jonathan Way, who works in Massachusetts for the National Park Service, claims in a forthcoming paper that it has. He thinks its morphological and genetic divergence from its ancestors is sufficient to qualify. But many disagree. One common definition of a species is a population that will not interbreed with outsiders. Since coywolves continue to mate with dogs and wolves, the argument goes, they are therefore not a species. But, given the way coywolves came into existence, that definition would mean wolves and coyotes should not be considered different species either--and that does not even begin to address whether domestic dogs are a species, or just an aberrant form of wolf.

What are eastern coyotes or coywolves?

Why can coywolves inhabit large cities?

Why does a coywolf in the city need only half the territory it would require in the countryside?

What does the example of coywolves‘ learning the Highway Code indicate?

Has the coywolf evolved into a distinct species? Why or why not?