NMNH in Review: Top Discoveries by Museum Scientists in 2023

Indigenous woolly dogs, ground sloth pendants and more headline-grabbing findings by scientists at the National Museum of Natural History

A white, fluffy dog stands in front of a brown mural with other dogs
A forensic reconstruction of the Coast Salish woolly dog alongside breeds of Arctic and spitz dogs. Karen Carr

2023 was a banner year for the National Museum of Natural History marked by the arrival of significant specimens, the unveiling of multiple exhibitions and hundreds of scientific publications. Join us for the “NMNH in Review” series over the next month to learn about a new orca specimen, historic asteroid samples and other exciting discoveries made by museum scientists this year. Read previous installments here.


Last year, researchers at the National Museum of Natural History authored hundreds of scientific papers. These publications identified new species, yielded insights into ancient world-changing geological processes and raised new questions about early humans and their relatives. Here are the top ten discoveries by NMNH scientists that garnered the most media coverage in 2023.

Ancient toolkit offers a glimpse of surprisingly handy hominins

Ancient human relatives used stone tools to butcher this hippo skeleton nearly 3 million years ago in Kenya. T.W. Plummer, Homa Peninsula Paleoanthropology Project

Many researchers think that only humans and other species in the genus Homo fashioned stone tools to tackle big game. But the discovery of a 2.9-million-year-old butchered hippo skeleton in Kenya raised new questions about this long held theory.

An international team of researchers including museum paleoanthropologist Rick Potts uncovered the carved-up hippo bones in western Kenya’s Homa Peninsula alongside some of the oldest known stone tools. Paleoanthropologists call these rudimentary instruments, which were used to slice flesh and pound plant material, the Oldowan toolkit. However, the team was surprised to also find a pair of massive molars at the site belonging to a species of Paranthropus, an ancient group of hominins closely related to humans. 

Potts and his colleagues published the discovery in the journal Science in February. The site’s teeth are the oldest fossilized Paranthropus remains yet found. Their presence at a site covered with stone tools raises intriguing questions about which human ancestor crafted and wielded these tools to butcher large animals like hippos. “Finding Paranthropus [teeth] alongside these stone tools opens up a fascinating whodunnit,” Potts said.

Early humans may have lived in a hominin-eat-hominin world

Nine cut marks on a fossilized hominid shin bone are all oriented in the same direction, suggesting that they could have been created by a stone tool. Jennifer Clark, NMNH
Deep in the fossil collections of Kenya’s Nairobi National Museum, Smithsonian paleoanthropologist Briana Pobiner scoured every inch of a 1.45-million-year-old hominin tibia. She was looking for bite marks that might tell her which prehistoric predators were hunting early human relatives, but the thin cuts that covered the bone told a very different story. Pobiner had uncovered an ancient case of potential cannibalism, suggesting that early hominins may have butchered each other for food.

In a study published in Scientific Reports, Pobiner and her co-authors analyzed 3D models of the fossil’s surface, comparing the cuts to hundreds of other tooth, butchery and trample marks that had been created during controlled experiments. The results revealed that nine of the cut marks were a clear match for stone tool damage, providing evidence for the oldest known instance of hominins butchering other hominins. Although Pobiner believes that the strategic location and uniform orientation of the cut marks make cannibalism the most likely scenario, further research will be needed to prove whether early hominins had their own evolutionary relatives on the menu.

Sloth pendants turn back the clock, suggesting an early arrival of humans in the Americas

Three sloth bones were carved and polished to be worn as personal ornaments over 25,000 years ago in Brazil. Department of Paleobiology, Smithsonian Institution

Long before evolving into the small and slow-moving creatures that we know and love, thousand-pound giant ground sloths roamed South America. Now, new research is suggesting that ancient communities may have lived alongside these monstrous mammals thousands of years before humans were thought to have arrived in the Americas.

Researchers discovered three modified sloth bones with polished surfaces and small holes drilled in the center hidden amongst a collection of stone tools in Brazil’s Santa Elina rock shelter more than 30 years ago. NMNH paleoanthropologist Briana Pobiner and paleontologist Thais Pansani, currently a postdoctoral fellow at the museum, worked with an international team of researchers to analyze these bones using non-destructive scanning technology, publishing their findings in the Proceedings of the Royal Society B in July. 

The team concluded that the bones had been deliberately crafted into pendants by humans living in the region between 25,000 and 27,000 years ago.  These dates may rewrite human history in the Americas, forcing anthropologists to re-evaluate the widely accepted theory that people migrated over the Bering land bridge in a single wave around 15,000 years ago.

Researchers uncover the genetic legacy of enslaved and free iron workers

Catoctin Furnace in Cunningham Falls State Park, Maryland. Aneta Kaluzna

For more than half a century, enslaved Africans and African Americans churned iron products like stoves, utensils and cannon balls out of Maryland’s Catoctin Furnace. But when the iron forge transitioned to a system of hired European immigrant workers on the eve of the Civil War, the contributions and histories of the site’s early enslaved and free workers were largely forgotten. 

A team of researchers recently set out to uncover the genetic legacies of these forgotten forge workers. Using a new genetic approach, scientists connected nearly 42,000 people living today to 27 African Americans who were buried near Catoctin Furnace in the late 18th–early 19th centuries.

The team included museum biological anthropologists Kari Bruwelheide and Douglas Owsley as well as researchers from Harvard University, Catoctin Furnace Historical Society and geneticists from the biotechnology company 23andMe. Their findings, published in the journal Science in August, analyzed the genetics of several historical individuals buried near Catoctin Furnace and compared the data with DNA information from more than 9 million living people. The highest concentration of potential descendants of the Catoctin group was in Maryland, indicating that some stayed in the region following the furnace’s transition away from enslaved labor.

Scientists discover a bevy of new soft-furred hedgehog species

A pair of Hylomys dorsalis soft-furred hedgehogs seen in the wild in Borneo, Malaysia. Quentin Martinez, all rights reserved

Compared with other groups of animals, mammals are largely well studied. This makes discovering a single new mammal species relatively rare. But in December, a team led by museum research zoologists Arlo Hinckley and Melissa Hawkins described five new species of soft-furred hedgehogs from the tropical rainforests of Southeast Asia. 

Hawkins and Hinkley collaborated with an international team of researchers to analyze the DNA of soft-furred hedgehogs, known to scientists as lesser gymnures. Using modern genomic techniques to examine tissue samples and prepared specimens, they identified five new gymnure species in a paper published in the Zoological Journal of the Linnean Society

Three of these gymnures were previously described subspecies that were actually distinct enough to be described as separate species. But the other two species were completely new to science. This includes Hylomys vorax, a small, shrew-like hedgehog with dark fur and a voracious appetite that lives in North Sumatra. The miniature mammal had been right under researchers’ noses for decades: the first H. vorax specimen was deposited in the Smithsonian’s collection 84 years ago.

160-year-old pelt sheds light on origin and sudden disappearance of Indigenous woolly dog

The 160-year-old pelt of the woolly dog Mutton in the Smithsonian’s collection. Brittany M. Hance, NMNH

For thousands of years, Coast Salish tribal nations in Washington State and British Columbia bred and cared for an Indigenous breed of woolly dogs. They sheared these dogs like sheep and wove their thick hair into blankets and other ceremonial items. The dogs themselves also possessed spiritual significance. 

In the mid-nineteenth century, this once thriving tradition was in decline when explorer George Gibbs adopted a woolly dog he called Mutton. When Mutton died in 1859, Gibbs sent the dog’s pelt to the nascent Smithsonian Institution, where it has resided ever since. Mutton remains the only known woolly dog fleece in the world. 

A team of researchers, including evolutionary molecular biologist Audrey Lin and anthropologist Logan Kistler, recently analyzed genetic clues preserved in Mutton’s pelt. They traced the woolly dog breed back some 5,000 years and pinpointed nearly 30 genes that likely contributed to the dogs’ highly sought-after woolly fur. The team collaborated with several Coast Salish co-authors including Elders, Knowledge Keepers, and Master Weavers, who provided crucial context about the role woolly dogs played in Coast Salish society and how the dogs’ memory continues to live on.

The world’s first bees evolved on an ancient supercontinent 

There are over 20,000 known bee species in the world, and researchers use high-definition imaging systems to compare their physical characteristics. Smithsonian Institution

Although bees play a critical role in many modern ecosystems, their evolutionary origins have remained a scientific puzzle that researchers have been trying to solve for decades. This August, an international group of researchers, including Smithsonian research entomologist Sean Brady, published a study in Current Biology that traced bee evolution back more than 120 million years to the ancient supercontinent Gondwana, which included Africa and South America.

The researchers sequenced the genes of over 200 modern bee species and compared them to traits found in bee fossils and extinct populations. They created a genealogical model that suggested the first bees originated from their wasp ancestors tens of millions of years earlier than previously thought. As new continents formed, bees diversified at a remarkable speed to follow the rapid spread of flowering plants. Understanding how bees evolved to fill their current ecological niches will help researchers in their efforts to keep modern pollinators alive and healthy in the future.

Smithsonian director helps inventory the global natural history collection

A small fraction of the more than 50 million specimens housed in the museum’s invertebrate zoology collection. Chip Clark, NMNH

Beyond the National Museum of Natural History’s exhibition halls and public displays are more than 148 million specimens and objects. But even a collection this large reveals only snapshots of the natural world’s vast story, making it difficult to gain a comprehensive understanding of the Earth’s past and forecast the planet’s future. Natural history museums around the world have similar gaps in their collections. 

Comparing the collections of the world’s natural history museums could help fill these knowledge gaps. NMNH director Kirk Johnson recently helped spearhead an effort to inventory the scientific holdings of 73 of the largest natural history museums in 28 different countries. In a paper published this past March in the journal Science, Johnson and more than 150 museum directors and scientists utilized a straightforward methodology to conclude that these museums collectively safeguard more than 1.1 billion specimens and objects. 

Learn more about the groundbreaking effort here

New clues about the rise of Earth’s continents

A microscope image of an area the size of a sugar crystal containing glass (brown), garnet (pink) and other small crystal structures. G. Macpherson and E. Cottrell, Smithsonian

Continents are an essential part of why Earth is uniquely habitable for life. Yet surprisingly little is understood about what gave rise to these crucial pieces of the planet’s crust. One key factor that differentiates continental crust is its lack of iron. The iron-poor composition of continental crust compared to iron-rich oceanic crust is a major reason why vast portions of the Earth’s surface stand above sea level as dry land, making terrestrial life possible today. 

Museum research geologist Elizabeth Cottrell and her colleagues recently tested and ultimately eliminated a popular theory that the crystallization of the mineral garnet, a process that incorporates iron, depleted the iron in continental crust. In a paper published in the journal Science in May, Cottrell and the team utilized laboratory experiments to recreate the massive pressure and heat found beneath continental arc volcanoes, where continental crust is formed. As the researchers grew samples of garnet crystals from molten rocks, they discovered that the garnet crystals did not incorporate enough iron from the rock to explain the iron-depletion in continental plate forming magma. Like many scientific findings, these results raise new questions about what sparked the rise of Earth’s continents.

A deep-sea dilemma: stressed jellyfish reveal dangers of seabed mining

Midwater helmet jellyfish (Periphylla periphylla) were collected using a remotely operated vehicle in the North Pacific Ocean. Vanessa Stenvers

The ocean’s midwater is the largest and least understood ecosystem on Earth. With over a billion cubic kilometers of living space, this section of the ocean between the seafloor and surface is home to countless fanged fish and bioluminescent jellies. Although the midwater remains largely unknown to science, this ecosystem is already facing a growing number of human-induced environmental pressures. Little is known about how denizens of the deep are responding to these stressors.

New research by NMNH invertebrate zoologist Vanessa Stenvers took a closer look at the effects of seafloor mining, which creates suffocating plumes of sediment that extend into the midwater ecosystem. In a paper published in Nature Communications, Stenvers and her co-authors investigated how the stress responses of midwater helmet jellyfish changed as they were exposed to simulated sediment plumes. 

The researchers found that the jellyfish had to produce excess mucus to remove the sediment from their bodies, and they began to express genes related to respiration, innate immunity and wound repair. These stress responses could lead to starvation and death if left untreated, and the research team hopes that their study may encourage mining companies to consider their environmental impact before it’s too late.

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