A road under construction is a pretty common sight.
The bulldozers and front end loaders.
The flashing lights and hardhats.
The mastodon bones and ancient stone tools.
Wait a minute, back up. Mastodon bones? Stone tools? That's different, right?
Yep, it is. So different, in fact, that a discovery made in a freeway construction site in San Diego might just change everything that we know about human history in North America.
The site in question, known as the Cerutti Mastodon Site, was first discovered back in 1992. Originally, it appeared to be the well-preserved remains of a mastodon, a prehistoric relative of the elephant. Pretty exciting already. But there were further clues there that made archeologists think that they were on to something a little more intereseting. There were sharpened stones that looked like tools next to the bones. Also, the bones looked like they had been broken in unnatural ways (in other words, by humans for food or to make tools).
25 years later, the result of their research is far more amazing than they could've ever dreamed! Now they believe that they have found evidence that humans living in North America around 130,000 years ago. That is over 100,000 years earlier than previously thought!
Just how huge a discovery is this? This paleontologist, Daniel Fisher from the University of Michigan, sums it up pretty well.
The way it was?
To understand what kind of a change to the history books this would be, let's take a look at the current storyline for humans getting to North America.
1: Homo sapiens, or modern humans, are believed to have originated in Africa around 200,000 years ago.
2: Over the next 180,000 years or so, humans slowly migrated across Asia and Europe.
3: Somewhere near the end of the last ice age (that's 23,000 to 15,000 thousands years ago), scientists believe that humans found their way to North America. They got here by crossing an icy land bridge between Siberia (northeastern Russia) and Alaska.
Sounds neat and tidy enough, right? So what is this new theory suggesting?
Ahead by one thousand centuries
If this new discovery is correct, it would mean a bunch of pretty incredible things. For one, the ancestors of Aboriginal peoples go back about 10 times further back than we once thought. But one very big fact would tower over all others.
If this is true, it means that humans managed to cross from Asia to North America before the land bridge between Siberia and Alaska existed. Which leads to the question: How on Earth did they do it?
For now, archeologists are asking for people to not jump to conclusions. After all, even though these mastodon bones and the "tools" have been dated to around 130,000 years ago, there are still no human skeletons in the area. Human bones that could be dated to this time would provide the ultimate proof. Until then, this is just a very interesting theory.
Do you believe that humans lived in North America over 100,000 years ago? For more on the site and the debate, check out this video.