As I’ve noted previously, humans are strange beasts and our reproductive biology illustrates this well. Menstruation and menopause are both rare in the animal kingdom. Of all mammals, only us, our primate relatives and elephant shrews menstruate. Menopause is even harder to come by — killer whales are our only sisters in hot-flushes, apparently.
This begs the question: why? How did each of these reproductive quirks evolve in humans?
I’ve written two pieces for The Conversation about the evolutionary theories that try to explain where menopause and menstruation come from. The first, about menopause, can be found here. The second, on why women menstruate, has also now been published.