Photograph by Nicole Duplaix
The male rhea, a large, flightless bird from South America related to the ostrich, has a bit of a wandering eye when it comes to mating. But no one could accuse him of being an absentee dad. Each mating season, male rheas build a nest and invite the members of their harem, up to 15 females, to deposit their eggs. The females then go off to look for other mates while the male stays to incubate the clutch, which can contain 25 to 50 eggs. For six weeks the father eats little and rarely leaves the nest. He then rears the hatchlings, defending them aggressively and charging any animal—even a female rhea—that approaches too closely.