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The science of skulls
Max Miller 46 min ago



The Buffalo Bill Center of the West’s Draper Natural History Museum has a new “specimen.” With his origin east of the Mississippi and an age of under 35 years, it’s unlike many of the museum’s other pieces.

On Feb. 1, Corey Anco made his debut appearance as the Draper’s new assistant curator, delivering a presentation based on his master’s thesis for Fordham University on the genetic history and drift of leopard populations in Africa.

“African leopards have far more genetic diversity than previously thought,” he told the crowd of around 50 that turned out for his 45-minute talk, part of the Museum’s Lunchtime Expeditions series of lectures.


Anco identified five genetically distinctive populations of leopards on the continent, with groupings in West Africa, Coastal West Africa, Central Southern Africa, Southern Africa and Central Eastern Africa.

Flipping to a Powerpoint map showing these population groupings, Anco said that by analyzing mitochondrial DNA from his samples, he was able to determine that it’s likely the species has origins in the continent’s central eastern region.

Samples collected from that region shared more direct genetic links to other regional populations than any other single group, according to an analysis Anco displayed pictorially with a branch and node diagram showing the central eastern leopard’s swarm of connections across the continent.

The researcher said that may be due to the constantly changing nature of the predator’s homeland, where “forests and savannahs have shrunk and grown many times,” as the climate changed. “Habitat conditions are defined by rainfall,” Anco said, but even during the driest of periods when savannahs overtook much of the leopard’s habitat, trees remained in the central eastern part of Africa.

He hastened to constrain his findings, however, noting, “I’m not saying African leopards should be broken down into several subspecies.”

For his research, Anco gathered 182 different genetic samples from leopards in 15 African countries. Some of the samples were minute skull fragments taken from museum collections around the world, while others were from fecal samples gathered by researchers working in Africa today.

While the DNA samples thus gleaned are destroyed through analysis, Anco said what he needs can be harvested from a piece smaller than a fingernail, making his research minimally destructive of specimens.

“We want to cause as little damage or alteration to the skulls as possible,” he said.

By only looking at mitochondrial DNA, Anco said his analysis was somewhat limited. Because that DNA is based only on the female line, he noted, “You’re looking at the picture with only one eye open, which is important to keep in mind.”

Mitochondrial DNA evolves 10 times faster than nuclear DNA, however, making it a rich site for research into change over time. For that reason, Anco said that type of DNA “is commonly targeted by museum researchers.”

Mitochondrial DNA is also more resilient against decay, and Anco was able to glean information from samples as far back as the 19th century, giving him access to population data from areas where the leopard is no longer part of the landscape.

He said the big cat’s domain has shrunken significantly in recent years. Studies suggest the large cat is found in only 25-37 percent of its historic range, though its doing slightly better in Africa, where it is believed to inhabit 48-67 percent of its former range.

The leopard’s nocturnal lifestyle can make it hard for researchers to estimate exactly where the feline is still active, Anco said.

But there are multiple factors threatening the species’ survival he said, most of them human caused.

One of those threats is man-made climate change fragmenting and diminishing leopards’ habitats, a development Anco said has created “ghost forest devoid of their natural fauna.” Other threats to the species include trade in the cat’s body parts for use in making traditional Asian medicines, trophy hunting and conflicts with livestock-raisers.

“When livestock and leopards overlap, humans tend to win,” Anco said.

At the Draper, Anco hopes to do similar research with the Museum’s collection of wolf skulls. He is also in touch with other institutions across the United States as he aims to learn more about the North American predator through similar mitochondrial DNA studies.

Anco said he’s excited to be involved in researching an animal that’s “inherently tied to this landscape.”

Speaking of the wolf, Anco said “it’s revered, it’s loathed, and it’s generated about every feeling in between.”

It would seem the dominant feeling the predator has generated in him is curiosity.