Much like the emperor penguin, the rhea is a large, flightless species of bird in which the male dutifully incubates the female’s eggs until they hatch. But this is where any similarities to the monogamous emperor penguin end. The male rhea, an ostrich look-alike and member of the ratite family, is a rampant polygamist that keeps a harem of up to 12 available females.
Despite his wandering eye and many mates, male rheas aren’t deadbeat dads in the least. In addition to incubating as many as 50 eggs at a time for six weeks — the daddy rhea is in charge of nest-building and is responsible for raising the chicks for the first six months without any assistance from multiple mothers. If anything threatening — be it a human or a female rhea — gets near daddy’s precious little ones, he won’t hesitate to charge. Although the rhea is native to South America, a male rhea that famously celebrates Father’s Day resides in Washington’s Smithsonian National Zoo.