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.