猛犸，這種在公元前2000年滅絕的生物，如今科學家們成功地重新構建了它的血紅蛋白，并發現它的血紅蛋白能在極低的溫度下運送氧氣。這一發現，也許能幫助科學家開發出用于低溫誘導治療的血液代用品，挽救很多人的生命。

When it came to surviving freezing weather, mammoths relied on more than their woolly coats: even their blood was specially adapted to let them thrive in chilly climes. Their hemoglobin functioned well over a larger range of temperatures than does the hemoglobin found in modern elephants—and in humans. That finding is in the journal Biochemistry. [Yue Yuan et al., "A Biochemical–Biophysical Study of Hemoglobins from Woolly Mammoth, Asian Elephant, and Humans"]

Mammoth veins have, of course, long run dry. But researchers from North America, the U.K. and Australia extracted fragments of nucleic acids from three mammoth specimens, creating hemoglobin based on its coding DNA sequence. The recovered mammoths died in Siberia between 25,000 and 43,000 years ago.

The reconstructed mammoth hemoglobin could deliver oxygen at colder temperatures than the human form of the protein could handle. With mammoth hemoglobin as a guide, scientists hope to engineer blood products that will oxygenate our bodies during those medical procedures—such as some heart and brain surgeries—that require the big chill known as induced hypothermia. Mammoths may be long dead, but the secrets of their blood could help keep some people alive.

—Sophie Bushwick