TOP TURKEY: A dominant tom develops striking secondary sexual characteristics, such as a bright, fleshy head and snood.© CREATIVEX/ISTOCKPHOTO.COMWith only a two-month window to court and mate with as many hens as he can, a dominant male wild turkey has his work cut out for him. Thankfully, one of his brothers often pitches in, helping to attract females and ward off potential competition from rival male pairs. But so long as a flock’s alpha male is alive, what his subordinate sibling won’t do is copulate with a single female bird. Establishing this pecking order in the first place requires a hard-fought battle, but one that results in a better chance at evolutionary success for both brothers. When they work as a team, related toms pass on shared genetic material to, on average, approximately six more offspring throughout their lifetimes than if either had tried to go it alone.
Having worked with wild turkeys nearly all her life, Victoria Roberts knows the male birds’ aggressive-turned-cooperative courtship rituals well. Most often, one bird eventually falls into line. While rare, the dominance battles between male birds can turn deadly. “When neither one of them wants to back down, that’s when they can have real, real fights—they can actually kill,” says Roberts, a poultry veterinarian from Yorkshire, U.K. “So being able to be submissive is actually lifesaving.”
University College London’s Judith Mank had been investigating differences in gene expression between sexually dimorphic phenotypes in several avian species when she first learned about the behavioral differences between dominant and subordinate male wild turkeys. Intrigued by the social arrangement, she and her colleagues decided to probe gene-expression differences between ...
