Wolves (canis lupus), coyotes (canis latrans), and domestic dogs (canis familiaris) are closely-related species. All three can interbreed and produce viable, fertile offspring — wolfdogs, coywolves, and coydogs.
Through DNA analysis, scientists have established that the wolf is the ancestor of the dog. Dogs and wolves are so closely related that DNA analysis cannot distinguish a wolf from a dog or a wolfdog hybrid. Coyotes, however can be distinguished from wolves and dogs through DNA analysis. Scientists can identify a coywolf from a coyote and a wolf, and a coydog from a coyote and a dog. The red wolf (canis niger) has been shown to be a coyote-wolf hybrid.
Wolves, coyotes and dogs are social creatures. Wolves form extended family groups consisting of the male and female, their young, and juveniles from the previous year's litter. They have a complex social hierarchy that allows for cooperative living, hunting, and defense of territory with minimal social stress, and still maintains temperament differences among individual pack members.
Coyotes had long been thought to be loners, living on their own except during breeding season. Recent research in Yellowstone National Park and elsewhere, however, has shown that coyotes, where they are not hunted by man, live in social groups like wolves. Like a wolf pack, the coyote pack includes the mated pair, their young, and several juveniles from the previous year's litter. Coyote packs hunt cooperatively and defend territories.
Federal and state governments spent millions of dollars to eliminate the wolf from the lower 48 states and succeeded, except for a few isolated populations in Michigan and Minnesota. Now that the wolf is indeed an endangered species, it is protected from exploitation by man, and efforts are underway to reestablish wolf populations. Federal and state governments still spend millions of dollars to eliminate the coyote, but in this they have failed. Instead, we have created a "super coyote"; the dumb ones have all been killed. Far from being endangered, the coyote has taken over the former niches of wolves and is now found in every state except Hawaii.
For dogs, humans form their social group. Dogs retain many characteristics of their wolf ancestor; but whereas the wolf is a generalist, the dog has been selectively bred by man over some 15,000 years to specialize in traits important to humans.