America was one of the last places humans colonised, with Homo sapiens only arriving there ~15,000-years-ago. However, in 2017 archaeologists found something that seemed to turn this on its head. Whilst supervising highway construction in California, they found the “Cerutti Mastodon site”1.
This collection of bones and tools appeared to show signs of human activity. The twist: it’s actually 130,000-years-old1!
Obviously, this threatened to shake up the history of humanity; making international news in the process. Crucially, it pushes back the occupation of America before we left Africa. So, if true, this would mean the first people in America weren’t just early, they weren’t even our species!
But the “if true” is a big sticking point. Since these findings were first published, archaeologists have been re-evaluating the site. Sadly for anyone looking to rewrite human history, their findings suggest the Cerutti Mastodon site has a much more mundane origin2.
The Cerutti Mastodon site
The discovery that’s causing all this fuss is a 50 square metre area near State Route 54 in San Diego. This nondescript spot was having a new sound barrier installed, until supervising archaeologists spotted something in the ground. The resulting excavations led to the discovery of more than 300 mastodon bone fragments, earning the locale the name “Cerutti Mastodon Site”. Or the less memorable, SDNHM locality 37671.
Crucially, the bones look like they’ve been hit with rocks. Meanwhile, rocks found at the site appear to have been used to hit bones. This was confirmed through experimental archaeology. Researchers hit elephant bones with rocks, documenting the resulting damage. It turns out it was very similar to what was seen at the Cerutti Mastodon site1.
This is classic evidence of hominin activity as we’re the only group that butchers meat with tools. As such, it wouldn’t be a big deal. That is until they carried out Th/U dating of the Mastodon fragments, revealing them to be 130,000 years old1.
Which, as I said earlier, is kind of a big deal for a site in California. In fact, no other equally ancient activity has been found. As such, all the evidence for early first Americans rests on these bones and rocks.
Initial debate over Cerutti Mastodon
As with any brand new discovery that threatens to re-write the textbooks, many were skeptical. After all, printing up new books is a hassle people don’t want to have to deal with. This prompted a flurry of back and forth, as scientists argued over the site.
- Some wondered if the ancient dates were reliable3 but the original authors had an expert in the technique back-up their findings4.
- Others asked where all the other evidence of these alleged early humans in America was3,5. The original authors contended the absence of evidence is not evidence of absence4.
- Yet others pointed out that all of these finds were made at a construction site. Can we be sure heavy machinery wasn’t responsible for the damage3,5?
This sort of back and forth went on for a little while. Whilst the discoverers of the site could respond to many of the points made, there was enough skepticism that most researchers were unconvinced. The lack of archaeological context, in particular, was a sticking point for many.
After all, by 130,000 years ago hominins had a complex culture, including early signs of art. In Africa, they’ve left behind literally trillions of stone artefacts. Yet despite all of this complex culture, the only trace these first Americans left were a handful of hammers in a Californian ditch. No other bones or tools, genetic traces in subsequent populations, or cool paintings in any caves.
A new challenger approaches
And that’s where the site sat for a while. There were enough reasons to be skeptical that most didn’t take it seriously, but it couldn’t be ruled out entirely. Enter Patrick Ferrell, who looked at the site from a different perspective: civil engineering.
He produced plans of the site, combining the records of California’s Department of transportation with photos of the Cerutti Mastodon site as it was being excavated. These revealed it was located near a drainage system being dug, and dump trucks carrying away the excavated material would drive right over the locale2.
Ultimately, hundreds of laden dump trucks would have driven right over the site, which was only protected by 30 cm of pliable earth. This pressure would have driven cobbles in the earth into the underlying bones, breaking them both in a manner that might look intentional. In reality, it’s just what happens when a bunch of lorries drive over some fossils2.
So, after a few years of research, it seems the Cerutti Mastodon site can be finally put to bed. The real culprit for the first “humans” in America was just modern humans driving heavy machinery. Which is sort of what I guessed when the finds were first announced.
- Holen, S.R., Deméré, T.A., Fisher, D.C., Fullagar, R., Paces, J.B., Jefferson, G.T., Beeton, J.M., Cerutti, R.A., Rountrey, A.N., Vescera, L. and Holen, K.A., 2017. A 130,000-year-old archaeological site in southern California, USA. Nature, 544(7651), pp.479-483.
- Ferrell, P.M., 2019. The Cerutti Mastodon Site Reinterpreted with Reference to Freeway Construction Plans and Methods. PaleoAmerica, pp.1-7.
- Haynes, G., 2017. The Cerutti Mastodon. PaleoAmerica, 3(3), pp.196-199.
- Holen, S.R., Deméré, T.A., Fisher, D.C., Fullagar, R., Paces, J.B., Jefferson, G.T., Beeton, J.M., Rountrey, A.N. and Holen, K.A., 2018. Broken bones and hammerstones at the Cerutti Mastodon site: a reply to Haynes. PaleoAmerica, 4(1), pp.8-11.
- Braje, T.J., Dillehay, T.D., Erlandson, J.M., Fitzpatrick, S.M., Grayson, D.K., Holliday, V.T., Kelly, R.L., Klein, R.G., Meltzer, D.J. and Rick, T.C., 2017. Were Hominins in California∼ 130,000 Years Ago?. PaleoAmerica, 3(3), pp.200-202.
- Ferraro, J.V., Binetti, K.M., Wiest, L.A., Esker, D., Baker, L.E. and Forman, S.L., 2018. Contesting early archaeology in California. Nature, 554(7691), p.E1.