Scientists say it's a find "unlike anything that we have seen." Deep within a South African cave, experts claim to have uncovered the remains of a previously unknown human ancestor that stood about 5 feet tall, weighed 100 pounds, used tools, and may have buried its dead—an activity previously thought to be exclusive to modern humans, NBC News reports. Homo naledi, which had a brain the size of an orange, "looks like one of the most primitive members of our genus, but it also has some surprisingly human-like features—enough to warrant placing it in the genus Homo," an anthropologist says. Researchers found 15 individuals of the species—including infants, children, adults, and seniors—after some rather slender scientists squeezed through a 7- or 8-inch-wide opening in the Rising Star cave near Johannesburg and descended 40 feet to a chamber below, report the Guardian and National Geographic.
Expert Lee Berger—who describes the species as "long-legged," "pinheaded," and "gangly"—says anthropologists explored various scenarios to explain why the remains were in such an isolated place, "including mass death, an unknown carnivore, water transport from another location, or accidental death in a death trap, among others." But "we have, after eliminating all of the probable, come to the conclusion that Homo naledi was utilizing this chamber in a ritualized fashion to deliberately dispose of its dead," Berger says. Others scientists are skeptical of that conclusion, and of the news that a new species has been found, arguing Homo naledi may only be a primitive Homo erectus, discovered in the 1800s. Dating the bones—which has been delayed because it will likely destroy the fossils—should eventually show where the species falls on the fossil record, and its relation to Homo erectus. (Read more evolution stories.)