DNA from old hair helps confirm the macabre diet of two 19th century lions

A pair of male lions that roamed Kenya more than a century ago gained notoriety because the “man-eaters of Tsavo.” To make certain that, the big cats hunted and ate people building a neighborhood railway. But a novel DNA analysis of hairs stuck inside the cats’ tooth cavities is revealing a a ramification of — and now and again surprising — menu.

The roughly 130-year-old dietary log consists of oryx, zebras and yes, humans, researchers report October eleven in Current Biology. Rapidly, traces of wildebeest also showed up: The herbivores weren’t known to roam the Tsavo region in the meanwhile, so the finding raises questions about how predator met prey. The analysis, which changed into sensitive enough to identify two separate giraffes from the same subspecies, shall be useful for better understanding the lifestyles of long dead animals and the ecosystems they lived in.

“The strategy opens up a new avenue of inquiry into the past,” says anthropological geneticist Ripan Malhi of the University of Illinois Urbana-Champaign. That will possibly potentially allow scientists to reconstruct diets from thousands of years ago.

The famed lions’ preserved skulls and skins have been housed at the Field Museum of Natural History in Chicago since 1925 and contain hints about what brought in regards to the animals’ predilection for hunting humans. As an illustration, both lions have damaged and broken teeth, that can have made eating from their typical menu of large, strong herbivores more tough.

Packed deep inside the cavities of the shattered fangs are hairs from mammals.

Malhi and colleagues wondered if DNA analysis methods for old, degraded hairs may spill the lions’ dietary secrets (SN: Three/22/23). Similar studies have probed the genetics of Siberian mammoths by studying the DNA in ancient hairs, says integrative evolutionary biologist Alida de Flamingh, also of the University of Illinois Urbana-Champaign.

“What makes our learn about unique is that in place of starting with a known animal, we are analyzing hairs and hair clumps to identify the animals that the hairs originated from,” she says.

The team extracted and transcribed DNA from the mitochondria — energy-producing structures in cells — in both single hairs and knots of hair. The researchers then in comparison the genetic blueprints to a database of over 20 different African animal species’ mitochondrial DNA.

The team found matches for a couple of prey species, including giraffe, oryx, waterbuck, zebra and wildebeest.

That last species is surprising: In 1898, the closest wildebeest grazing area to where the lions were killed changed into about ninety kilometers away. “It means that the Tsavo lions can have either traveled farther than as much as now believed, or that wildebeest were present inside the Tsavo region right through that time,” de Flamingh says.

For some detected species, the researchers had enough DNA to transcribe your entire, extra-detailed set of mitochondrial DNA – the mitogenome. By comparing the giraffe mitogenomes, the team determined that the hairs came from two distinct, individual giraffes.

Tyler James Murchie, a paleogenomicist at the Hakai Institute on Calvert Island, British Columbia who changed into not involved with the research, is surprised that the DNA fragments survived for this long inside the lions’ mouths inside the museum. The assorted menu changed into also surprising, he says. “These lions were reasonably a success, it'd seem, having this fashion of diet breadth whatever the one [lion] having this fashion of major tooth fracture.”

The researchers also detected human DNA inside the predators’ dental detritus, adding to other research confirming the lions’ reputation as “man-eaters”.

Now that the team has developed this method of reconstructing predators’ past diets, they wonder if the hair deposits shall be studied in more detail.

De Flamingh compares hair clumps to layers of soil. “Layers lower in lower parts of the tooth cavity represent prey eaten earlier in life and layers at the head of the cavity are from recently eaten prey,” she says.

Comparing the DNA between the layers may reveal changes in predators’ diets over their lives, possibly by reason of the human-lion conflict, which is ongoing broadly across Africa, de Flamingh says. Additionally, dental injuries like inside the Tsavo lions are every so often suggested as a traumatic event that pushes lions to hunt humans and domesticated animals. Such shifts may show up in stacks of fragmented hairs.

“This learn about nicely exemplifies how a superior deal unique, hidden genetic information also may be lurking inside the crevice of a bone or artifact in a museum somewhere that’s just anticipating a clever researcher to ask an spell binding question,” Murchie says.