Scientists studying two mummified baby woolly mammoths found in the Siberian Arctic have announced new details about the animals' short lives -- and gruesome deaths.
Researchers at the University of Michigan believe that both of the 40,000-year-old babies, nicknamed Lyuba and Khroma, suffocated in mud -- Lyuba after falling through lake ice, Khroma after tumbling into a river. Through a dental analysis on both Ice Age animals, researchers also learned that Lyuba was likely one month old when she died. Khroma was about two months old.
(Story continues below.) A photograph of Lyuba’s external appearance prior to any internal examination.
The scientists also suspect that Khroma had nursed just before her death, because her stomach contained remnants of undigested milk. "It looked like you'd just popped the top on a container of yogurt," study author Daniel Fisher, a paleontologist at the University of Michigan, said in a written statement. "It was that white. It was that smooth. Just fresh, creamy milk from mama mammoth."
CT images showing the head and shoulders of Lyuba (top) and Khroma (bottom). The labels indicate inhaled sediment in the baby mammoths’ airways.
Both specimens were so well preserved scientists could see their muscles. Adam Rountrey, a collections manager at the university's Museum of Paleontology, told NBC News that Khroma's muscle tissue was "bright red, and looked like fresh meat," while Lyuba's resembled beef jerky.
Close analysis of the animals' skeletons confirmed their similarity to modern elephants.
Scans of Khroma’s skull showed that her brain was comparable to a newborn elephant's, but slightly smaller. This finding suggests that mammoths may have had shorter gestation periods than elephants do.
“We’ve learned with direct, physical evidence how similar they are: how similar in family structure, life history, and very similar bodies,” Fisher told Wired.
Billed by the American Museum of Natural History as the "most complete and best-preserved baby mammoth specimens ever found," Lyuba and Khroma's remains may continue to shed light on other baby mammoth specimens found in different locations.
“This is the first time anyone’s been able to do a comparative study of the skeletal development of two baby mammoths of known age,” Fisher said in the statement. “This allowed us to document changes that occur as the mammoth body develops. And since they are both essentially complete skeletons, they can be thought of as Rosetta Stones that will help us interpret all the isolated baby mammoth bones that show up at other localities.”
Fisher said the new research also helps advance ideas about mammoths' extinction.
"We know it's part of a larger process that involves the extinction of the other animals of the Ice Age," Fisher told The Huffington Post. "We're not with this work solving that problem of extinction -- that's about 3-4 papers down the line -- rather it's our work on these baby mammoths that give us critical insight into the biology and ecology of mammoths that will by and by be critical in understanding the cause of extinction."
Reindeer herders came across Lyuba's frozen body in 2007. Khroma was discovered one year later, roughly 3,000 miles away in northeast Siberia. After a squabble over who would get to study the specimens, Lyuba's remains were moved to a Ford Motor Company testing facility in Michigan in 2010 and scanned by its massive industrial-sized computed tomography (CT) machine, which ordinarily is used to inspect car parts. Khroma underwent CT scans at two French hospitals.
Scientists first reported initial findings of their examinations of Lyuba and Khroma nearly three years ago, NBC reported.
Findings from the complete study were published online July 8 in a special issue of the Journal of Paleontology.