By the Late Cretaceous, alvarezsaurs had dispersed to other continents.

到白垩纪晚期，alvarezsaurs 已经分散到其他大陆。

The shrinking of the alvarezsaurs lines up neatly with the diversification of ants, termites, and bees.

alvarezsaurs 的缩小与蚂蚁、白蚁和蜜蜂的多样化完全一致。

Also, like today's social insect specialists, alvarezsaurs had no teeth in the front of their mouth.

此外，像今天的社会昆虫专家一样，阿尔瓦雷兹龙的嘴巴前面没有牙齿。

And the alvarezsaurs seem to have had weak jaw bones, probably because chewing becomes less important when you're eating ants.

alvarezsaurs 的颚骨似乎很脆弱，可能是因为当你吃蚂蚁时咀嚼变得不那么重要了。

The ancestral Jurassic alvarezsaurs in China are estimated to have averaged 23 kg in body mass.

据估计，中国祖先侏罗纪阿尔瓦雷兹龙的平均体重为23公斤。

Most of the alvarezsaurs we've found weighed less than 50 kilograms.

我们发现的大多数 alvarezsaur 体重都不到 50 公斤。

So, what pushed the alvarezsaurs towards developing smaller body sizes?

那么，是什么促使 alvarezsaurs 发展出更小的体型呢？

One of these early alvarezsaurs was Haplocheirus.

这些早期的 alvarezsaurs 之一是 Haplocheirus。

Beginning about 130 million years ago, we find two more alvarezsaurs in China.

从大约 1.3 亿年前开始，我们在中国又发现了两只阿瓦雷兹龙。

And alvarezsaurs may have reduced competition with other theropod dinosaurs that had gotten bigger and become apex predators by becoming insect-eaters.

alvarezsaurs 可能减少了与其他兽脚类恐龙的竞争，这些恐龙已经变得更大，并通过成为食虫者成为顶级掠食者。

So, by the Late Cretaceous, the alvarezsaurs had miniaturized, while evolving stubby front arms with a single, clawed finger and simple teeth.

因此，到了白垩纪晚期，alvarezsaurs 已经小型化，同时进化出粗短的前臂，带有单个爪状手指和简单的牙齿。

Those two dinosaurs fill the gap in the fossil record between their Jurassic ancestors and the Late Cretaceous alvarezsaurs, and their transitional features hint at what was to come.

这两种恐龙填补了它们的侏罗纪祖先和晚白垩世阿瓦雷兹龙之间的化石记录空白，它们的过渡特征暗示了即将发生的事情。

Mononykus belonged to a group of dinosaurs called the alvarezsaurs, which are thought to have originated in Asia and would ultimately include 21 species over time.

Mononykus 属于一组称为 alvarezsaurs 的恐龙，它们被认为起源于亚洲，随着时间的推移最终将包括 21 个物种。

While it's clear that alvarezsaurs were already diverse during the Late Jurassic, they were all probably carnivores like most other theropods -- they just seemed to be after smaller prey.

虽然很明显在侏罗纪晚期，阿尔瓦雷龙已经多样化，但它们可能和大多数其他兽脚类动物一样都是食肉动物——它们似乎只是在捕食较小的猎物。

So, while the first alvarezsaurs were carnivores, the rise of social insects during the Cretaceous Terrestrial Revolution seems to have pushed them into a new niche -- one that was new for them and new for dinosaurs.

因此，虽然第一批 alvarezsaurs 是食肉动物，但白垩纪地球革命期间群居昆虫的兴起似乎将它们推向了一个新的利基市场——这对它们来说是新的，对恐龙来说也是新的。