I've seen this in action with some of the small mammals I've studied up close. The way their bodies react to light cycles is pretty wild. When the days get shorter, it's not just about the melatonin—it's about the whole system shutting down. The testes don't just shrink, they basically go dormant. It's like the body is saying, "Not the time for babies." But it's not just about size. The function is gone too. You don't just get smaller organs, you get less active ones. It's a full system reset. I've seen it in action, and it's not just a little change. It's a complete shift.