人类按照24小时一循环的作息规律来生活，是因为大脑中有昼夜节律钟的协调。 研究发现，驯鹿等北极动物，在北极持续数周白天或黑夜里生活时，是没有昼夜节律钟的。 How Its Internal Clock I...
There's a Santa's carrier. For Tom Scheib, today is one of those days he spends most of the year preparing for. Let's just put the harness out right here. This is his time to make any last-minute adjustments and see that his team is in good spirit an...
提起reindeer（驯鹿），大家眼前肯定浮现出这样一幅画面：在冰天雪地里，圣诞老人坐着雪橇赶着驯鹿，带着好多精致的礼品去送给那些可爱的孩子们。你...
