Coyotes Invade Chicago, Faithful to Mates for Life

Oct. 3, 2012 — -- Even his face gives him away. The devilish smirk says it all: the coyote cannot be trusted. Always up to no good, cheating on its mate, abandoning its kids, disappearing for long periods while others pick up the slack.

Nothing, it turns out, could be further from the truth, at least among the hundreds of coyotes that have abandoned the country life for the big city of Chicago.

Scientists have been studying the urban coyotes that apparently feel perfectly at home in the nation's third largest city for 12 years now, and the evidence is clear: Coyotes make better husbands than a lot of men. They mate for life, and hang around to help raise the kids, and they go their separate ways only when one of them dies.

"I've never believed in that old adage 'til death do us part,' at least in the natural world, but that's the only thing we've seen so far in this study," wildlife ecologist Stan Gehrt of Ohio State University said in a telephone interview. Gehrt began focusing on the coyotes of Chicago in 2000, and he and colleagues Cecilia Hennessy and Jean Dubach have compiled a huge data bank on 236 coyotes, including 18 litters comprising 96 offspring.

The coyotes were captured repeatedly over a six-year period, radio-collared, and then released in the same area after their blood was drawn. The blood samples yielded a complete DNA profile of the animals, and showed that in every case, year after year, pups were produced by the same two parents.

It may sound corny, but that genetic evidence proves the coyotes did indeed mate for life, both sexually and socially. That doesn't mean, of course, that all coyotes are like that. But it's just the opposite of what Gehrt thought he would find when he started the project. He started at the request of the Cook County Animal Control agency, which had found itself inundated by calls from Chicago residents a bit uneasy over an exploding population of coyotes in their city.

An urban setting is actually a good place for coyotes, if you look at it from their point of view. There's plenty to eat in easily accessible garbage cans, not to mention the occasional stray cat, and there are no hunters or trappers. The coyote population in the Chicago metropolitan area was already well over 1,000 when the project began. The combination of a rich resource, and many coyotes, could only add up to promiscuity, the researchers expected. They got a surprise.

"I thought this was going to be the perfect test of how monogamist coyotes are," Gehrt said, "because they have so many opportunities to deviate. That's why I was so shocked that time after time, year after year, we found the same pattern."

The genes told the story. Mom and Pop were staying together, and the new kids were always theirs, and only theirs.

That's rare among mammals. Only 3-5 percent of mammalian species are believed to be monogamists, and that estimate is based almost entirely on observation, not genetics. The canine world has the greatest number of monogamists, especially foxes and wolves and coyotes, but this is the first study based on genetics showing that monogamy is the rule, at least in Chicago.

It's not known for certain why monogamy thrives in the canine world, with occasional missteps, but it's probably because newborn pups require a lot of parenting.

"If the father isn't really dedicated to helping raise those pups they have no chance of surviving," Gehrt said. "The mother won't be able to raise them alone, and it's probably going to cost her her life if she tries."

Pop needs to bring home the bacon and keep predators away if the family is to make it.

Incidentally, monogamy is far more common among birds than mammals, probably for the same reasons. Someone has to sit on the eggs while the mate gathers food, and in some cases, teaches the kids how to fly.

Swans and bald eagles are known to mate for life. Swans seem particularly affectionate, but it isn't all romance. Just migrating, establishing territory, and raising their young doesn't leave much time for shopping around for a little extracurricular fulfillment.

Nonetheless, staying with one mate for an entire lifetime carries some liabilities.

"It still surprises me," Gehrt said. "It's hard to explain why there wouldn't be at least some cheating going on," just to improve the odds that some of the genes that will be passed on from the other parent are desirable.

"If they are truly staying together and mating with only one individual until they are dead, the decision of who their partner is is pretty darn important," he said. "Why don't they hedge their bet a little?"

But there were no exceptions, based on the genetic testing, except for one couple who raised some pups that probably belonged to a close relative.

The coyotes in this study stayed together until one of them died, and then in nearly all cases, the surviving mate just left.

"They move to a completely different area, many miles away," Gehrt said.

"We tracked one female for 11 years until she died," he added. "She had only one mate. They hooked up together in 2003 and they produced a litter every single year. We captured them (the pups) every year and they were always from those two.

"So they were monogamists, and then, last year, she died of natural causes. She just simply came to the end of her life and she left this male who had lived in this one area for almost 10 years. Sure enough, he left.

"He moved to a completely different area where he found another female, and they had a litter."

Why did he move so far away? Gehrt speculates that perhaps he abandoned the family home to his offspring. Of perhaps he was chased away by other coyotes. Who knows?

"We just know there's an awful lot of coyote soap opera going on out there," Gehrt said.