Fight geometry shapes size dimorphism

Whether males evolve larger bodies often depends on the spatial geometry of male–male competition: two‑dimensional fighting (on land) tends to favor bigger, stronger males, while three‑dimensional combat (in air or water) favors smaller, more agile males. This ecological detail helps explain why some taxa show female‑biased size and others show male‑biased size. — Bringing the 'fight geometry' explanation into public discussion tempers simplistic claims that 'biology' uniformly favors one sex over another and shows sex differences depend on ecology and behavior, which matters for policy and cultural debates.