The Fascinating Mystery of Homo naledi

Homo naledi, an extinct species of human not ancestral to Homo sapiens, is known from just 1 fossil site in the entire world–Rising Star Cave in South Africa. The remains consist of 15 individuals that apparently were buried in the same location over time. They were discovered during 2013 and anthropologists believe they were deliberately buried, though Homo naledi had a much smaller brain that modern humans. The discovery spawned a fascinating mystery. Why did a primitive species of human bury their dead in the same location? Anthropologists don’t believe humans with such a small cranial capacity could have a concept of an afterlife. The burial pit is pitch dark. They must have used torches to see inside the chamber, but anthropologists don’t think humans this primitive could have mastered fire. Some anthropologists don’t think the site is a deliberate burial pit. They suggest the bodies were simply thrown down a shaft or were carried by flood water. However, the majority of anthropologists who have examined the evidence do believe the bodies were deliberately buried.

Scientists used a variety of dating techniques to determine the age of the Homo naledi remains including uranium-thorium decay, optically stimulated luminescence, electron spin resonance, and paleo-magnetic analysis. They determined the bones range in age from 414,000 years BP-236,000 years BP. This means Homo naledi co-existed for a while with our ancestors: Homo erectus or maybe even Homo heidelbergensis. An anatomical analysis determined they shared characteristics with Australopithecus and Homo genuses, but they should be placed in the latter genus. They could walk upright just like us, though they were better climbers than modern humans. On average adults were less than 5 feet tall and weighed less than 100 pounds. Dental evidence suggests they are dirt-covered roots and bulbs. The location is some distance away from an area rich in game, so they may have existed in a spot where predators such as leopards were less common. They probably used tools. No other evidence of this species may ever be discovered. They diverged from our ancestors at least 900,000 years ago, and we likely will never know very much about our distance cousins.

References:

Dirks, P., et. al.

“The Age of Homo naledi and associated sediments in the Rising Star Cave, South Africa”

Evolutionary Biology May 2017

Irish, J., et. al.

“Ancient teeth, Phenetic Affinities, and African Hominins: Another Look at where Homo naledi fits in”

Journal of Human Evolution 122 September 2015