恐龙父母是怎么知道他们的孩子什么时候发烧的?

恐龙父母是怎么知道他们的孩子什么时候发烧的?

From the time that dinosaur fossils were first discovered, these creatures have fascinated scientists and laypeople alike. In the academic world, their remains provide important clues into the prehistoric world; in popular culture, dinosaurs have inspired blockbuster hits, such as Jurassic Park and King Kong.

从恐龙化石被发现开始，这些生物就吸引了科学家和普通人。在学术界，他们的遗骸为我们了解史前世界提供了重要的线索;在流行文化中，恐龙激发了无数电影大片的灵感，如《侏罗纪公园》和《金刚》。

Now, a research team headed by Professor Hagit Affek at the Hebrew University of Jerusalem's Institute of Earth Sciences has unlocked a mystery that has stymied researchers for decades: How did dinosaurs regulate their body temperatures? Were they warm-blooded or cold-blooded?

现在，由耶路撒冷希伯来大学地球科学研究所的Hagit Affek教授领导的一个研究小组，揭开了一个困扰研究人员数十年的谜团：恐龙是如何调节体温的?他们是温血动物还是冷血动物?

Affek's study, published today in Science Advances, relies on a novel method to measure historical temperatures. Called clumped isotope geochemistry, this method analyzes chemical bonds among heavy isotopes in calcium carbonate minerals—the main ingredient in egg shells. This allows scientists to calculate both the temperature at which the minerals formed and the body temperature of the mother that laid the egg.

今天发表在《科学进展》杂志上的Affek的研究，依靠一种测量历史温度的新方法。这种方法被称为块状同位素地球化学，它分析了蛋壳主要成分碳酸钙矿物中的重同位素之间的化学键。这使得科学家可以计算出矿物质形成的温度和产蛋母亲的体温。

Affek and her team applied this method to fossilized eggs from three distinct dinosaur species along the evolutionary path from reptile to bird and found that their body temperature ranged from 35-40 degrees Celsius. However, this bit of information still did not answer the question as to whether dinosaurs were endothermic or exothermic, meaning, did they generate their own body heat or get warm from the sun and their environment?

Affek和她的团队，将这种方法应用于从爬行动物到鸟类的三种不同的恐龙蛋化石，发现它们的体温在35-40摄氏度之间。然而，这些信息仍然没有回答恐龙是吸热还是放热的问题，也就是说，它们是自己产生热量，还是从太阳和它们的环境中获得热量?

The global climate during the dinosaur era was significantly warmer than it is today. For this reason, measuring only the body temperatures of dinosaurs who lived near the equator wouldn't tell us whether they were endo- or exothermic because their body temperature may simply have been a cold-blooded response to the hot climates they lived in, shared Affek.

“恐龙时代的全球气候比现在暖和得多。因此，仅仅测量生活在赤道附近的恐龙的体温，并不能告诉我们它们是吸热还是放热的，因为它们的体温，可能只是对它们生活的炎热气候的一种冷血反应。”

To address this issue, her team focused on dinosaurs that lived in high latitudes like Alberta, Canada—far enough north to ensure that their warm body temperatures were the result of an internal, metabolic warming process rather than merely reflecting the climate around them.

为了解决这个问题，她的团队把重点放在了生活在像加拿大阿尔伯塔这样高纬度地区的恐龙身上，因为那里的纬度足够高，可以确保它们温暖的体温是内部新陈代谢变暖过程的结果，而不是仅仅反映了它们周围的气候。

To verify their hypothesis, Affek and her team needed to determine the environmental temperature in Alberta back when dinosaurs lived. They accomplished this by applying their isotope method to mollusk shells that lived in Alberta alongside the dinosaurs. Since mollusks are cold-blooded creatures, they reflect the ambient climate of the time. The mollusks' body temperature measured 26°C and showed that the dinosaurs living in Alberta were endothermic; otherwise, they could not have maintained a body temperature of 35-40°C.

为了验证假说，Affek和她的团队需要确定阿尔伯塔省恐龙生活时期的环境温度。他们将同位素法应用于与恐龙生活在一起的亚伯达省的软体动物壳上，从而实现了这一目标。由于软体动物是冷血动物，它们反映了当时的环境气候。这些软体动物的体温为26℃，这表明生活在阿尔伯塔省的恐龙是吸热的;否则，他们就无法保持35-40℃的体温。

As dinosaurs evolved, they moved from lizard-like (cold-blooded) characteristics to avian (warm-blooded) ones. "We believe that this transformation happened very early on in dinosaurs' evolution since the Mayasaura eggs—a lizard-like dinosaur species that we tested—were already able to self-regulate their body temperature, just like their warm-blooded, bird-like cousins, the Torrdons," explained Affek.

随着恐龙的进化，它们从类蜥蜴(冷血动物)特征转变为类鸟类(温血动物)特征。“我们相信这种转变在恐龙进化的早期就发生了，因为Mayasaura蛋——一种我们测试过的类似蜥蜴的恐龙物种——已经能够自我调节它们的体温，就像它们的温血表亲，鸟类一样。”Affek解释道。

The fact that both of these species, located at opposite ends of the dinosaur evolutionary tree, had body temperatures higher than those of their environment means that both had the ability to warm themselves.

这两个物种都位于恐龙进化树的两端，它们的体温都高于周围环境的温度，这意味着它们都有保暖的能力。