时差N小时:史前的牙签

If asked to imagine the first prehistoric tools,crafted and used by our early, hominid ancestors,you'd probably think of crude knives or spear heads,chipped from stone.You probably aren't aware ofanother human innovation that might be just asold. Today we'll learn about the two million yearhistory of the toothpick, possibly one of humanity'soldest tools.

如果让你去想象做工粗糙，人类最早的祖先使用过的史前牙签，你可能会想到由石头磨成的原始刀具或者矛枪尖。你可能没有意识到另一种同样古老的革新。今天我们就来了解200万年的牙签历史，这可能是人类历史上最古老的工具之一。

Early stone tools, like knives and scrapers, are easy for anthropologists to learn aboutbecause these items are still around. Even after two million years, a chipped stone tool is stillgoing to be there when you dig it up. Toothpicks, however, are another story. Made fromsplinters of wood, thorns, or bone fragments, these can rot and crumble away over time,leaving no recognizable trace. If this is so, how can an anthropologist look at a two millionyear old fossil site and claim that these early pre-humans picked their teeth?

早期的石头工具，如小刀和刮刀，让人类学家很容易理解，因为在现代社会仍然存在这些东西。即使再过200万年，这些东西仍然埋在地里。然而牙签却是另一回事了。大多数牙签由木头的碎片、荆棘或者骨头碎片制成，会随着时间的流逝腐烂消失，不留下任何可辨别的痕迹。如果是这样的话，为什么人类学家会只凭着200万年前的化石遗址，就声称古代史前人类也用牙签剔牙?

It's certain that no toothpick will ever last two million years, but this isn't the case withteeth. In fact, fossil teeth are the most durable remnants that anthropologists work with, andsome of these ancient teeth display a curious set of grooves. Although these might have beencaused by tooth decay, a close examination of the marks seems to indicate that the grooveswere worn by repeated toothpicking--probably to alleviate the pain of gum disease. Indeed,these fossil grooves match the toothpick grooves in the teeth of several modern aboriginalpopulations.

可以肯定的是，没有牙签会保存200万年，但牙齿却不一样了。事实上，牙齿化石是人类学家所研究的最持久的残留物。这些古时人类的牙齿上排列着一道道凹槽，很令人好奇。尽管这可能是由于蛀牙引起的，但经过进一步仔细检查，证明这些凹槽似乎是因为长期剔牙而形成，古人类剔牙也可能是为了减轻牙龈疾病引起的疼痛。事实上，不少现代土著居民的牙齿上也出现了凹槽，并与化石上的凹槽相匹配。

It's enough to warm every dentist's heart: The first tools weren't just for preparing food,hunting, or fighting. They might have been used for dental hygiene as well.

这足以温暖每一位牙医的心：第一个工具不只是为了准备食物，为了狩猎或战斗，也可能是为了保持牙齿卫生。