In my recent article “The Genus Homo: All in the Family,” I noted that other members of our genus have skeletons very close to those of modern humans. Intellectually, Neanderthals have been found associated with signs of art and culture. But what about Homo erectus? Much of their technology and culture is inferred indirectly and remains something of a mystery. But after writing a chapter on the fossil record for Science and Human Origins, I discovered a fascinating story that suggests Homo erectus was capable of building boats and traveling over the sea–an activity which would have required very high intelligence.

It started recently when I picked up a popular science magazine, Science Illustrated at an airport before getting on an flight for a work-trip. I’d never purchased this magazine before, but an article mentioned on the cover about Homo erectus looked intriguing. The article was titled “Who was Homo erectus,” by Jørn Madsen of the Natural History Museum of Denmark, and it suggested reasonable evidence that Homo erectus built boats and was capable of seafaring over moderate distances of water:

While no remains of a boat used by H. erectus have been found (the oldest known vessels, Stone Age dugouts, are only a few thousand years old), potential evidence of the species’ habitation on isolated islands suggests that it may have been able to travel many miles across the open sea.

In 2008, Russian researchers found very primitive stone tools on Socotra, a completely isolated island more than 150 miles off the Horn of Africa and 240 miles off the coast of Yemen. … The researchers estimate their discoveries to be anywhere from 500,000 to 1 million years old, which is firmly within the time frame of H. erectus.

(Jørn Madsen, “Who was Homo erectus,” Science Illustrated (July/ August 2012), p. 23.)

The article recounts that it’s difficult to date the tools precisely, but they are of the type known to be produced by erectus in this time period. The article gives further examples:

[A]dditional discoveries made in Crete also lend support to the theory. In 2008 and 2009, Greek and American archaeologists found a number of crude stone tools near the island’s southwest coast. Among the more than 2,000 objects they unearthed were coup de poings, stone tools with two sharp blades. These were found in deposits that were dated to at least 130,000 years ago…

The article continues:

To accomplish any seafaring journeys, Dr. Karl Wegmann of North Carolina State University says, “They had to have used some sort of boat, though we will probably never find preserved evidence of one.” He acknowledges that this discovery weakens the idea that earlier hominids were landlocked. “We all have this idea that early man was not terribly smart. The findings show otherwise–our ancestors were smart enough to build boats and adventurous enough to want to use them.”

When I got home and Googled this story, it turns out it’s all over the internet on science-news websites. A 2011 story on Phys.org states:

A team of researchers that included an North Carolina State University geologist found evidence that our ancestors were crossing open water at least 130,000 years ago. That’s more than 100,000 years earlier than scientists had previously thought.

Their evidence is based on stone tools from the island of Crete. Because Crete has been an island for eons, any prehistoric people who left tools behind would have had to cross open water to get there.

The tools the team found are so old that they predate the human species, said Thomas Strasser, an archaeologist from Providence College who led the team. Instead of being made by our species, Homo sapiens, the tools were made by our ancestors, Homo erectus.

Likewise a 2010 article in Wired Magazine states, “Stone hand axes unearthed on the Mediterranean island of Crete indicate that an ancient Homo species — perhaps Homo erectus — had used rafts or other seagoing vessels to cross from northern Africa to Europe via at least some of the larger islands in between, says archaeologist Thomas Strasser of Providence College in Rhode Island.” National Geographic put it this way:

Many researchers have hypothesized that the early humans of this time period were not capable of devising boats or navigating across open water. But the new discoveries hint that these human ancestors were capable of much more sophisticated behavior than their relatively simple stone tools would suggest.

“I was flabbergasted,” said Boston University archaeologist and stone-tool expert Curtis Runnels. “The idea of finding tools from this very early time period on Crete was about as believable as finding an iPod in King Tut’s tomb.”

Even the journal Science has a similar (though unrelated) story from years ago titled, “Ancient Island Tools Suggest Homo erectus Was a Seafarer.”

The point of all this is that other members of our genus Homo don’t represent unintelligent, non-human, ape-like forms. They looked a lot like us, and there’s increasingly good evidence that they thought a lot like us too. As I recently discussed, some scientists even suggest that Homo erectus, Neanderthals, and Homo sapiens were really just the same species. When our genus Homo appears in the fossil record, it does so abruptly, very different from previous forms, and without evolutionary precursors.