Even the eyes of mammals that were diurnal—active only during the day—had certain characteristics of nocturnal eyes, like those of creatures who are active at night.

即使是昼夜活动的哺乳动物的眼睛——只在白天活动——也具有夜间活动的眼睛的某些特征，就像在夜间活动的生物的眼睛一样。