: In the world of stag beetles, males engage in spectacular fights in which they use their giant mandibles to try to grab opponents and hurl them over their heads. The fighting is all part of the species’ elaborate mating ritual. Although males have larger heads and mandibles than females, their bite strength is disproportionately much stronger. To find out why, Jana Goyens of the University of Antwerp in Belgium and colleagues took CT scans of the insects’ heads. They found
that the males’ wider heads accommodate internal levers and muscles that are 3–4 times as large as those of females.