For the next few months, visitors to the Perot Museum of Nature and Science in Dallas will have a rare opportunity to see fossils of ancient hominids up close.
A new exhibition, “Origins: Fossils from the Cradle of Humankind,” open through March 22, brings to the museum Australopithecus sediba and Homo naledi. The discoveries of these South African species over the last decade have raised new questions about humans’ family tree (SN: 12/23/17 & 1/6/18, p. 24).
Almost as amazing as the fossils themselves is the fact that they traveled to the United States. “Origins” marks the first time these fossils have been displayed outside of South Africa, and Dallas is their only scheduled stop.
“There’s something really distinct in our modern world about being able to see something … that’s authentic, that really is 2 million years old or 300,000 years old, and you’re there just inches from it rather than seeing it in virtual reality or on your computer screen,” says Becca Peixotto, director of the museum’s Center for the Exploration of the Human Journey
“Origins” focuses primarily on two specimens. First there’s Karabo, the male A. sediba skeleton that paleoanthropologist Lee Berger’s 9-year-old son Matthew discovered at a site called Malapa in 2008. Karabo, at the time of his death, about 1.97 million years ago, was close to Matthew’s age. Then there’s Neo, one of over a dozen H. naledi individuals found deep in the Rising Star cave system near Johannesburg in 2013 (SN: 10/3/15, p. 6). Neo, an adult male, lived about 300,000 years ago, about the time H. sapiens emerged (SN: 6/10/17, p. 6).
The exhibition encourages visitors to compare the mix of physical traits that these hominids had, in the same way scientists might as they piece together where species fit in humans’ evolutionary story. A panel points out how A. sediba had hands, feet, teeth and hips similar to modern people’s, yet also had small brains and long, apelike arms. In analyzing A. sediba’s features, Berger, of the University of the Witwatersrand in Johannesburg, has argued that A. sediba is a contender for a direct ancestor of the genus Homo (SN: 8/10/13, p. 26).
As scientists have discovered more and more fossils, it has become clear that the traditional view of human evolution as a “march of progress,” with a straight line of species leading to H. sapiens, is too simplistic, says Berger, who oversaw the discoveries of A. sediba and H. naledi. “What we’re seeing, as we get a clearer picture, is that we grossly underestimated the complexity of hominids in the past.”
What “Origins” does best is showcase the process of science — to the point of putting actual working scientists on display. Researchers can apply to study the fossils during the exhibition’s run — “as long as they do it in front of the public,” says Linda Silver, the museum’s chief executive officer. About halfway through the exhibition is a glass-enclosed lab where researchers can work while visitors watch.
One way of getting people to trust science, Berger says, is to understand its process — and to see the real deal.
For visitors, coming face-to-face with the real deal begins with Karabo, whose skeleton is roughly 30 percent complete, according to Berger. A nearby case displays a rocky sphere that probably contains the rest of Karabo’s bones, allowing visitors to see how the fossils are typically found.
Visitors have several opportunities to learn about the process of science. In one section, a “video tree” describes H. naledi’s discoveryand shows scientists from different specialties talking about their work on the species. A map and 3-D model of the Rising Star cave system are also on display. Visitors can attempt to squeeze through the tiny opening — 18 centimeters wide — of a life-size model of the entrance to the chamber where Peixotto and five other scientists dropped 12 meters down to excavate H. naledi fossils.
After visitors see Neo’s skeleton, the exhibition concludes with a re-created dig site, where visitors become paleoanthropologists and search through a large box of sand containing 15 fossil models. After photographing their finds with iPads, visitors can go to a science tent for a guided analysis of the images. “It’s kind of realistic because one of the things we’re starting to do is leave more [fossils] in place” in the field, Peixotto says. But Neo’s and Karabo’s excavated bones are meant to inspire visitors. “Just being able to see those real things,” Peixotto says, “there’s a sense of awe and an emotional connection that’s really important for us in understanding that these are our common roots as a species.”