American Scientist

To the Editors:

In the article “The Latest on Homo naledi” (Spotlight, July–August), I was captivated by the caption of an illustration on page 199 of the Dinaledi Chamber stating that the Superman’s Crawl and Dragon’s Back passages are each less than 25 centimeters in diameter. I read the article expecting some statement about how the current humans, who are presumably larger than the remains of Homo naledi they found, moved through these tight confines. My hips alone seem to be about 13 or 14 inches wide (33 to 36 centimeters), and my ribs and shoulders wider, so I was curious how people nowadays are able to pass through diameters less than 9.8 inches. I found no answer in the article. Caving is not for me—claustrophobia would get the best of me—but I do admire anyone who could squeeze through those passages and collect specimens.

Kai Baumann
Baden, PA

Dr. Hawks responds:

The measurements in the article indicate the smallest dimension of these “squeezes” in the cave. For the “Chute” that our team uses to descend into the Dinaledi Chamber, this smallest dimension is 18 centimeters. These squeezes are not circular, however, so that our cavers and excavators can align the front-to-back dimension of their chests with the smallest dimension through the squeeze. My body, like that of most of our scientists, does not fit through these narrow passages, but our underground team includes people with the right dimensions and climbing skills to manage them. If you’d like to see this maneuvering in action, a short video of our caver Rick Hunter passing through the “Superman’s Crawl” squeeze is on YouTube: https://youtu.be/NvqO77mA6hg.