科学美国人60秒 早期哺乳动物也会有社交生活

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Seventy-six million years ago, a group of small mammals huddled¹ in a burrow² in what’s now Montana. They were good diggers—most likely furry—and petite.

七千六百万年前，一群小型哺乳动物挤在现在的蒙大拿州的一个洞穴里。它们擅长挖掘——长着毛——而且身材娇小。

“They could sit comfortably in the palm of your hand. These things, if you saw them running around today, you’d think it’s a small rodent—a chipmunk³ or mouse.”

它们可以舒服地坐在你的手掌上。如果你现在看到它们跑来跑去，肯定以为是小老鼠——花栗鼠或老鼠。”

Lucas Weaver⁴ is a mammal paleobiologist at University of Washington.

卢卡斯·韦弗是华盛顿大学哺乳动物古生物学家。

These little creatures didn’t belong to any of the three main mammal groups on the planet today—which are the placental mammals (like us), monotremes (like the platypus) and marsupials (like koalas and kangaroos).

这些小动物不属于当今地球上三种主要哺乳动物——胎盘哺乳动物(例如我们)、单孔目哺乳动物(例如鸭嘴兽)和有袋动物(例如考拉和袋鼠)。

Instead they belonged to another, now extinct group called the “multituberculates.”相反，它们属于另一种现已灭绝的类群，叫做“多瘤齿兽”。

“They have these really bizarre molars with multiple bumps, which is where they get their name. Multituberculate. just means ‘many bumps.’”

“它们有非常奇怪的臼齿，上面有许多凸起，这也是它们得名的原因。”Multituberculate。只是意味着‘很多颠簸’。

Weaver and his colleagues have studied the fossilized skulls⁵ and skeletons of these animals, dug up in Montana, and they’ve given them a name: Filikomys primaevus (friendly or neighborly mouse).

韦弗和同事研究了在蒙大拿挖出的这些动物的头骨和骨骼化石，并给它们起了一个名字:Filikomys primaevus(友好或邻居老鼠)。

The details are in the journal Nature Ecology & Evolution.

研究详情发表在《自然生态与进化》杂志上

Weaver says drought or climate change may have killed the animals, though it’s hard to be sure. But the critters were fossilized together in ways that suggest they sought out each others’ company. That’s a big deal because it’s commonly thought that social behavior didn’t arise in mammals until after the death of the dinosaurs⁶, 10 million years after these small critters hung out together.

韦弗说，虽然很难确定，但干旱或气候变化可能是导致这些动物死亡的原因。但这些生物一起被石化表明它们在寻找彼此的陪伴。这是一件大事，因为人们普遍认为哺乳动物的社会行为是在恐龙灭绝后才出现的，在这些小动物一起生活了1000万年后才出现。

“The narrative⁷, for decades, has been that mammals living during the time of dinosaurs were mostly solitary⁸ ratlike creatures scuttling⁹ in the night under dinosaurs. And so the fact we’re finding these multituberculate mammals—a totally unrelated group of mammals—exhibiting social behavior means this was probably not uncommon¹⁰ among these early Mesozoic mammals. And it changes the narrative that sociality is somehow unique to placental mammals.”

几十年来，一直有一种说法是，生活在恐龙时代的哺乳动物大多是夜间在恐龙脚下独自奔跑的鼠形动物。事实上，我们发现这些多瘤哺乳动物——一组完全不相关的哺乳动物——表现出社会行为意味着在这些早期中生代哺乳动物中，这可能并不罕见。它改变了社会性是胎盘类哺乳动物特有的说法。”

Even today, social behavior is relatively¹¹ rare among mammals. But these findings suggest the need for company in some mammalian species is an ancient evolutionary¹² invention.

即使在今天，哺乳动物的社会行为也相对少见。但这些发现表明，某些哺乳动物物种是古代文明进化的结果。

1 huddled   

挤在一起（huddle的过去式与过去分词形式）

参考例句：

• We huddled together for warmth. 我们挤在一块取暖。
• We huddled together to keep warm. 我们挤在一起来保暖。

2 burrow   

vt.挖掘(洞穴)；钻进；vi.挖洞；翻寻；n.地洞

参考例句：

• Earthworms burrow deep into the subsoil.蚯蚓深深地钻进底土。
• The dog had chased a rabbit into its burrow.狗把兔子追进了洞穴。

3 chipmunk   

n.花栗鼠

参考例句：

• This little chipmunk is hungry.这只小花栗鼠肚子饿了。
• Once I brought her a chipmunk with a wound on its stomach.一次，我带了只腹部受伤的花栗鼠去找她。

4 weaver   

n.织布工；编织者

参考例句：

• She was a fast weaver and the cloth was very good.她织布织得很快，而且布的质量很好。
• The eager weaver did not notice my confusion.热心的纺织工人没有注意到我的狼狈相。

5 skulls   

颅骨( skull的名词复数 )； 脑袋； 脑子； 脑瓜

参考例句：

• One of the women's skulls found exceeds in capacity that of the average man of today. 现已发现的女性颅骨中，其中有一个的脑容量超过了今天的普通男子。
• We could make a whole plain white with skulls in the moonlight! 我们便能令月光下的平原变白，遍布白色的骷髅！

6 dinosaurs   

n.恐龙( dinosaur的名词复数 )；守旧落伍的人，过时落后的东西

参考例句：

• The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
• Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》

7 narrative   

n.叙述，故事；adj.叙事的，故事体的

参考例句：

• He was a writer of great narrative power.他是一位颇有记述能力的作家。
• Neither author was very strong on narrative.两个作者都不是很善于讲故事。

8 solitary   

adj.孤独的，独立的，荒凉的；n.隐士

参考例句：

• I am rather fond of a solitary stroll in the country.我颇喜欢在乡间独自徜徉。
• The castle rises in solitary splendour on the fringe of the desert.这座城堡巍然耸立在沙漠的边际，显得十分壮美。

9 scuttling   

n.船底穿孔，打开通海阀（沉船用）v.使船沉没( scuttle的现在分词 )；快跑，急走

参考例句：

• I could hear an animal scuttling about in the undergrowth. 我可以听到一只动物在矮树丛中跑来跑去。 来自《简明英汉词典》
• First of all, scuttling Yu Lung (this yuncheng Hejin) , flood discharge. 大禹首先凿开龙门（今运城河津市），分洪下泄。 来自互联网

10 uncommon   

adj.罕见的，非凡的，不平常的

参考例句：

• Such attitudes were not at all uncommon thirty years ago.这些看法在30年前很常见。
• Phil has uncommon intelligence.菲尔智力超群。

11 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

12 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。