Fiery Bones: New Study Reveals One of The Oldest Evidence of Deliberate Fire Use Over 1 Million Years Ago

Recent study reveals a rapid, non-destructive method for detecting burnt bone, extending one of the world’s oldest paleo-fire records.

Inside Wonderwerk Cave. Credit: Atlas Obscura

Myths across the world, from ancient China to Polynesia, in Native American stories, and beyond, tell the tale of how humans first attained fire. In some versions, it is one of the gods who steals or gifts fire to humanity. In others, humanity obtains it from the gods, sometimes through dubious means. One of the best-known fire myths concerns the ancient Greek Titan Prometheus, who stole fire from the Olympian gods to give to mortals, which led to the rise of civilization.

In many myths, humans obtaining fire is linked to them starting civilizations or entering an age of prosperity, and it is no wonder, as the emergence of fire use in the genus Homo marked one of the most transformative turning points in our evolutionary story. Fire provided warmth, protection, light, and eventually cooking.

But finding evidence of early fire use is difficult. Just because something is burnt does not mean ancient humans were using fire. Additionally, sometimes objects and artifacts, such as bones, may appear burned, but the color change actually results from natural processes. At the Wonderwerk cave in South Africa, Dr. Dolores Marin-Monfort and her colleagues developed a non-destructive technique to detect evidence of burning and, in doing so, uncovered one of the earliest pieces of evidence of intentional fire use, dating back 1.79 million years.

Obtaining Fire

Veld fire. Credit: Umphafa

Fire was a major turning point in human evolution, but pinpointing when humans first started using fire has been a bit more difficult. It is believed that the earliest humans did not make fire themselves, but rather gathered it opportunistically from natural wildfires, keeping it going for as long as possible at their camps. It is thus that researchers actually have two big questions they try to answer when dealing with early evidence of fire. First, when did humans first begin deliberately using fire, and second, when did humans begin making it?

The oldest evidence we have of deliberate fire use comes from Africa, where the dry savannah landscape naturally lent itself to frequent seasonal veld fires. In fact, natural fires are so common that the continent has sometimes been nicknamed the ‘fire continent’.

Various African sites have been proposed as showing early evidence of fire use, among them are Swartkrans and Koobi Fora. However, the problem with some of these sites is that the deposits from which they came have been disturbed (e.g., burnt material was washed in from somewhere else), or could have been natural (e.g., burning at open-air sites or close to shelter entrances could result from veld fires). Similarly, some of the best evidence for deliberate fire use, such as stone tools, butchered bones, and repeated burning at a single site, is often missing from the earliest sites.

But identifying when Homo first started using fire matters because it sets the stage for later ‘domestication’ of fire and regular cooking. Regular cooking would have boosted calorie intake, reduced digestive effort, and likely fueled brain growth, likely aiding in Homo erectus’s spread out of Africa.

The Wonders of Wonderwerk Cave

Beaumont during excavations of Wonderwerk Cave. Credit: Kimberley Museum in Horwitz & Chazan 2015

Wonderwerk Cave is located in the Northern Cape Province of South Africa at the base of the Kuruman Hills. Although the cave lay along a well-traveled route to the Moffat Mission and was mentioned by European travelers as early as the 1840s, its scientific importance would not be discovered until much later. 

During WWII, the Bosman family began commercial farming the rich bat guano in the cave, leading to the discovery of various fossil bones and stone tools. The finds were sent to Johannesburg, finally sparking formal archaeological investigations in the cave. B.D. Malan excavated the cave in 1943–45; a geological study was conducted in the 70s; and extensive excavations were done by P. Beaumont between 1978 and 1996, revealing nearly 2 million years of human occupation.

Since 2004, an interdisciplinary project has been underway, re-examining some of the earlier finds, including evidence that its deepest layers represent one of the earliest known intentional cave occupations in the world. And as it turns out, perhaps one of the earliest deliberate uses of fire in the world from Stratum 10 (St 10) and Stratum 11 (St 11) over 1 million years ago.

How to Detect Fire

This figure compares burnt and unburnt fossils (verified by FTIR) under different lighting and filter setups to capture a luminescence effect, using red, orange, and blue light filters alongside spectro-radiometer measurements. The images show that blue light (455 nm) with an orange filter best reveals the luminescence, while red filters produced images too dark to clearly display the effect. Credit: Marin-Monfort et al. 2026

A common method for detecting intentional burning is to examine the color of the bone. Burnt bone can range in color from light brown to chalky white, with shades of brown often interpreted as mild burning, while shades ranging from black, grey, and white are classified as evidence of more intense burning. However, color can be misleading, as other natural processes can change the color of bones, for example, manganese staining (a type of black staining).

Researchers may also examine bone texture (cracking, flaking, shrinkage) using specialized techniques such as SEM/BSE-EDS and Raman spectroscopy to distinguish true burning from natural chemical staining. While these methods are non-destructive, they can be expensive, slow, and require equipment you simply can’t take into the field. 

Raman, for example, uses equipment large enough to fill a room the size of a bakkie (pickup truck), and requires near-total darkness during analysis lest outside light messes with the laser.

An alternative, widely used method to confirm burning is Fourier Transform Infrared spectroscopy (FTIR). However, the method has a key weakness: it cannot reliably detect burning below ~537°C. This means the method probably vastly undercounts how often burnt bone actually occurs.

To address this, the researchers at Wonderwerk Cave developed a new, non-destructive method, adapted from forensic techniques, that uses the bone’s luminescence (how it glows) to determine whether it is burnt. The method uses an Alternate Light Source to illuminate the bone specimen with light of various wavelengths through optical filters. 

However, luminescence also has a drawback: it does not work on black bones because black absorbs light rather than reflecting it. Thus, the researchers combined FTIR with luminescence to confirm whether the bones at Wonderwerk Cave, including those from St 10 (~1 million years old) and the older layer St 11 (~1.79 to 1.07 million years old), were burnt.

187 bones were chosen, 161 from Wonderwerk, 13 modern experimentally burnt bones, and 13 fossils from Forat de la Conqueta (Spain). Forat de la Conqueta was included to test whether the luminescence & FTIR methods worked on burnt bones from contexts other than Wonderwerk. All bones were first sorted by color, including calcined (white and grey), charred (black and brown), and unburnt (yellowish/beige).

The results showed that 32 bones from St 11, 21 from St 10, 12 from Forat de la Conqueta, and all 13 experimental bones were confirmed to be burnt using both methods, save for black, which could not be tested by luminescence but was confirmed by FTIR. Under luminescent light, burnt bones glowed brightly, while unburnt bones emitted no light, and those which had been altered by something other than burning only shone very dimly.

The results confirmed two things: first, the combined method could be used to test for burning easily, quickly, and in bulk, making it ideal for field use; and second, Wonderwerk has some of the earliest evidence of intentional fire use.

There Was Fire

This figure illustrates the luminescence and Stokes shift caused by short-wavelength excitation (a) and how a long-pass filter restricts the observed spectral range (b). Microscope images show fossils under blue ALS light (455 nm) (c), and with a long-pass filter (580 nm cut-off) that makes burnt fossils appear reddish while unburnt fossils disappear (d). Credit: Marin-Monfort et al. 2026

Now you may think, “Great, there was a fire,” but couldn’t the bones have been burnt during a veld fire? 

No…

What makes Wonderwerk so special is that its deposits are in their original contexts, aka, they were not washed in from somewhere else. Where they were located is exactly where they were over 1 million years ago. And that location is about 30 meters from the entrance, meaning those bones would not h

This fire had to have been brought in. And this did not occur just once, but multiple times, as indicated by concentrations of burnt bones found in both St 10 and St 11, around 5 meters apart and separated by thousands of years. Meaning someone brought fire into the Cave over a million years ago, and then someone else did the same thing thousands of years later.

The researchers also make an interesting observation. The cave floor is carpeted with small animal bones, likely brought in by predators such as owls. And you may not know this, but owls regurgitate the bones, feathers, and fur of their prey a few hours after feeding.

I learned this while working at a bird of prey center. I was told that if I didn’t see a pellet in the coop, I wasn’t allowed to feed the bird. Why? Because they had not regurgitated their pellet yet, and if I feed them again, they might choke.

Fun fact over, what do pellets have to do with fire? Feathers and fur are highly flammable, so if you place your recently scavenged veld fire on a floor filled with pellets, it may help spread, feed, and maintain that fire for a bit longer. Pretty neat trick if you ask me.

This fire was probably not used for cooking, as no evidence of that exists at Wonderwerk, but it may very well have paved the way for cooking. The finding highlights the need for reliable, non-destructive methods, such as the luminescence approach, to confirm early evidence of fire, and provides evidence of the world’s oldest deliberate fire use to date.

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A recent study at Wonderwerk Cave pushed back the world’s oldest evidence of fire use by over a million years. While the precise timing of when early humans first began producing fire themselves remains unresolved, this evidence confirms that early hominins, most likely Homo erectus, deliberately brought fire deep into Wonderwerk over thousands of years.

Another fun aside, the San, the first inhabitants of southern Africa, also have a fire myth. In their myth, the trickster god /Kaggen (Mantis) notices an enticing smell. Following this smell, he spies Ostrich cooking food over a fire before hiding the flames under his wing. 

Knowing Ostrich will not give up the fire willingly, /Kaggen lures Ostrich to a fruit tree, telling him that if he wants the best fruit, he needs to reach for the very top of the tree. In doing so, Ostrich raises his wings, revealing the fire he is hiding. /Kaggen uses the opportunity to steal the fire and share it with the San people. This is also the reason ostriches cannot fly, as they want to preserve the little fire they have left by pressing it tightly against their sides.

Do you know any fun fire myths, and do you think the owl-pellet trick was deliberate or accidental?

References

Horwitz, L.K., Chazan, M. Past and Present at Wonderwerk Cave (Northern Cape Province, South Africa). Afr Archaeol Rev 32, 595–612 (2015). https://doi.org/10.1007/s10437-015-9208-5

The Mantis and the San | Stories from Namibia. (n.d.). Www.gateway-Africa.com. https://www.gateway-africa.com/stories/The_Mantis_San.html

‌Marin-Monfort, M. D., Shaw, C. L., Natalio, F., Grossman, L., Andrews, P., Campos, J., … & Fernández-Jalvo, Y. (2026). New evidence for Early Pleistocene use of fire at Wonderwerk Cave (South Africa). PloS one, 21(6), e0347480. https://doi.org/10.1371/journal.pone.0347480

The Noble Mantis: Wisdom of the San people. (2022, October 5). Path to the Maypole of Wisdom. https://maypoleofwisdom.com/the-noble-mantis-wisdom-of-the-san-people/