Fisher was also intrigued by the forensic mystery of how and why such an apparently healthy young life had been cut short—and whether it had anything to do with the odd deep dent in her face. "That feature immediately leaped out, though at the time I had no idea what to make of it," Fisher says.

To begin the analysis, tissue samples from Lyuba were sent to the Netherlands, where carbon-14 dating revealed she had died some 40,000 years ago. For scientists to probe deeper into her life, however, she would have to travel herself. In December 2007 Buigues arranged for the specimen to be transported to Japan by refrigerated container to undergo a CT scan by Naoki Suzuki of the Jikei University School of Medicine. The test confirmed her skeleton, teeth, and soft tissues were undamaged, and her internal organs seemed largely intact. The end of her trunk and her throat, mouth, and windpipe were filled with dense sediment, which suggested to Fisher that she had died by asphyxiation in mud. The scan also revealed some odd x-ray-opaque blobs in her soft tissues and a distortion of certain bones. These anomalies underscored another conundrum: After 40 millennia in the ground—and who knows how long exposed on the surface—why was she so well preserved?

Lyuba's remarkable condition appeared all the more mystifying in May 2008, when Fisher and Buigues visited the Yuribey River. Just upriver from the sandbar where she'd been found stood a high, sheer bluff, which was being steadily under­cut by the river. Blocks of permafrost, some as big as houses, hung out over the rim of the bluff. Perhaps Lyuba had been frozen in such a block that had collapsed into the water during the previous thaw, floated downstream, and come to rest on the sandbar when the thaw-swollen river had briefly risen to that level. There was only one problem: Yuri Khudi's sons had found her there in May 2007, before the spring ice-out. Unless she had risen from the underworld and walked up onto the bar on her own, the only explanation was that she had broken out of the permafrost and come to rest there nearly a year before she was discovered, during the ice-out of June 2006. To Fisher, standing on the spot two years later, it just didn't make sense.

"She'd have been lying on this riverside all that time," he said to Buigues, "including an entire summer exposed to the sun. So why hasn't she decomposed or been scavenged?"

Fisher and Buigues had done what they could to understand the circumstances of the calf's death and mysterious preservation. Further answers would have to come from Lyuba herself.