One hell of an impression
February 23, 2018
During a Greek holiday in 2002, a Polish paleontologist found what he thinks are the oldest human-like footprints in the world. Thus began a vicious fight over a discovery that raises new questions about our evolution.
Gerard Gierlinski’s trip to the Greek island of Crete in 2002 was meant to be a romantic getaway for him and his girlfriend. But it ended up becoming considerably more momentous than that — leading to a discovery that could dramatically alter the story of the human race.
It was Gierlinski’s first time on the island, a popular holiday destination for Poles like himself. He and his partner, Beata Piechik, were there to walk the sandy beaches, swim in the Mediterranean Sea and enjoy food and wine in the quiet tourist village of Trachilos, which is dotted with small houses and a handful of hotels.
“It’s an amazing, beautiful area,“ Gierlinski recalled in his Polish-accented English. But being a paleontologist at the Polish Geological Institute, Gierlinski was also prepared to record any discoveries he might make.
“I always carry — even on vacation — a hammer, a camera and a GPS,” he said.
So when he spotted an odd imprint in a rock along the beach, he was ready.
Gierlinski has studied dinosaur tracks and recognized the indentation as a footprint. And there were others. It was around noon, and the sunlight was too harsh to enable him to see the full details of the impressions — but he could immediately tell that they weren’t dinosaur tracks. He took a number of photographs of the imprints (including one with Piechik sitting on the rock). And, crucially, he captured the GPS co-ordinates, so he could find the place again.
‘This was like a shock for me.’
They eventually headed back home from their idyllic holiday, but Gierlinski couldn’t get those prints out of his head. For eight years, he wondered about them. In 2010, he found a good deal on an all-inclusive package and went back to Crete — and felt compelled to return to that spot. (By this time, he had broken up with Piechik.)
It was almost evening when he revisited that flat slab on the beach, one that tourists often sit on as they drink and gaze out at the sea. This time, the long shadows clearly revealed the outline of the footprints — prints that clearly resembled the shape of his own foot.
“This was like a shock for me,” Gierlinski said.
He eventually brought in other experts from Poland, as well as from Sweden, Greece, the U.S. and England, to help him analyze the footprints and the sediments surrounding them. Together, they determined the tracks were left by ancient human relatives 5.6 million years ago. That would make them the oldest human-like footprints in the world — two million years older, in fact, than the oldest found in Africa, long considered the “cradle of humankind.”
Gierlinski said it could suggest an unexpected and untold part of the story of where humans came from. “It’s a new frontier in the study of our ancestors,” he said.
The footprints have suffered a number of indignities since the discovery — from being sprayed with graffiti to being chiselled from the rock and stolen. But the bigger scandal may be the reception Gierlinski and his colleagues faced after they first reported their find.
No pre-human fossils that old have ever been found in Europe, and Gierlinski’s claim generated vicious criticism and disbelief from other scientists in a field where most influential researchers are committed “Africanists.”
Per Ahlberg, a researcher at Uppsala University in Sweden, was the member of Gierlinski’s team who took responsibility for getting the research published, and described the process as “six and a half years of sort of living hell.”
Gierlinski’s find casts a light not only on the often chance nature of scientific discovery, but the sometimes fierce conflict among the humans in the scientific community, who often bristle when their beliefs are challenged by new ideas — especially ones that may be ahead of their time.
II. Older than the oldest
Gierlinski is no stranger to astonishing discoveries. In the past, he found the feather imprints from a dinosaur’s belly that had rested on the mud millions of years ago in Massachusetts. He was also one of the co-authors of a study of footprints that suggested dinosaurs “danced” to attract mates, in much the same way some modern birds do. Those discoveries piqued people’s interest, but didn’t cause much controversy.
But when Gierlinski saw the Trachilos footprints for the second time and recognized their human-like shape, he realized that he had found something extraordinary.
After returning to Poland, he looked up the age of the sediments in Trachilos and was amazed to learn they were from the Miocene era. In layers of rock and sediments, the start of the Miocene is marked by a deposit left when the Mediterranean Sea temporarily dried up about 5.6 million years ago.
That was before a group of human-like footprints were left in volcanic ash at Laetoli, Tanzania. The 3.66-million-year-old Laetoli footprints have long been regarded as the oldest human-like footprints in the world.
The Miocene also predates Ardipithecus, a fossil hominin with an ape-like foot that lived in modern-day Ethiopia 4.4 million years ago and is thought to be part of the human lineage.
After his second visit to Trachilos, Gierlinski felt he urgently needed to go back a third time to further study the prints, and he needed other experts to assure him that what he thought they were was true — in other words, that he wasn’t crazy.
After a party in Warsaw several weeks after his second visit, Gierlinski showed pictures of the prints to two fellow researchers, Grzegorz Niedzwiedzki and Andrzej Boczarowski. He was going back to Crete in a few days — did they have time to come? They jumped at the chance.
When they arrived in Trachilos in November 2010 and began cleaning the surface of the slab of rock, they realized that it was embedded with not just one or two but dozens of fossil footprints — shallow impressions left in sand long ago that later hardened into rock.
Niedzwiedzki had recently started a postdoctoral fellowship with Ahlberg at Uppsala University and got him involved in the project. Ahlberg, in turn, suggested it would be a good idea to involve Greek researchers and the Greek Ministry of Heritage and Culture, and get permits before proceeding further.
Since the researchers initially involved in the project were experts in animal rather than human tracks, the team also got help from Matthew Bennett, a researcher at Bournemouth University in the U.K. who had studied the Laetoli footprints.
The Trachilos footprints are quite small, the largest no more than 23 centimetres long — roughly the size of a women’s size six shoe. The team found that “in the front, the toes are very human-like,” Gierlinski said. But the heel is narrower, like that of a chimpanzee or gorilla.
Ahlberg agreed that the toes were “remarkably human-like,” except that the creature’s big toe seemed more mobile. “They can wiggle it around a bit more,” he said.
The prints clearly belonged to creatures that normally walked on two feet. They kept their feet close together, like humans, rather than waddling, as chimpanzees do.
“What’s also very telling is we have no palm prints … nor are there any knuckle prints,” Ahlberg said.
He also noted that based on the orientation and placement of the tracks, the creatures didn’t seem to be going anywhere in particular. “The impression you get subjectively is of a little troop of these guys just sort of hanging out, just doing their thing in that sort of vaguely disorganized way that a troop of chimpanzees might do.”
The researchers think the creatures that made the prints could potentially be part of the human family tree. Or, they could potentially have been from another branch of upright-walking ape that happened to have developed similar feet — something they think is less likely.
Gierlinski said it was the most extraordinary find of his career. These are “the oldest human-like tracks in the world, unexpectedly found in Europe, not in Africa,” he said. “Obviously, it’s very important.”
In 2011, the researchers were ready to share these exciting findings with the world. And that’s when the trouble began.
III. ‘Savagely hostile’
What happened next provides a window into the world of scientific publishing, where discoveries must run a gauntlet of all-too-human gatekeepers before becoming official and public.
The team started submitting the research to peer-reviewed journals. Since this appeared to be something extraordinary — the oldest human-like footprints in the world — they started with high-profile publications such as Nature.
Since the editors of scientific journals aren’t experts on every topic, they typically send submitted manuscripts to expert peer reviewers to evaluate the quality of the research.
Many of the reactions to the Trachilos discovery were negative, to say the least. Ahlberg has been publishing papers since 1989 — including in Nature and Science — and had never experienced anything like this before.
“We got ferociously aggressive responses saying this couldn’t possibly be true and these can’t be footprints at all,” said Ahlberg. “In every round [of reviews], there would be at least one, and sometimes several, reviewers who were in the first instance savagely hostile. They would just flatly deny that these would be human or hominin footprints. They would say almost anything — they’re bear or monkey [tracks] or whatever.”
Ahlberg shared some of the reviews with CBC, and they appeared to match his descriptions, but warned that they could not be reproduced for confidentiality reasons.
One sarcastic reviewer referred to them as “mystery artifacts” and said the manuscript should be buried. Another reviewer, who claimed to approach the research with an open mind, alleged the prints showed only two features of hominin footprints — two features that Ahlberg pointed out never appear together in any group of animals except hominins.
The researchers addressed any criticism they could with further measurements, but the rejection letters continued to pile up as the researchers moved from one journal to the next.
Ahlberg alleged many of the reviews accused the authors, who were mostly experts in ancient footprints, of incompetence in interpreting tracks. But the reviewers provided no evidence to support their criticisms.
“Basically, it wasn’t a true peer review process at all,” he said. “They were just trying to shut us down.” One editor rejected the paper even though two out of three reviews were positive, which is unusual.
Gierlinski said he doesn’t blame the reviewers, as he often reviews papers himself and “sometimes I am not so nice also.” But he said he was frustrated with the journal editors who rejected the paper outright in response to the reviews, instead of giving the researchers the chance to make changes in response to the criticism.
Peer review is supposed to be a confidential process and researchers are not supposed to share unpublished work that they’re reviewing. But Ahlberg said he and his colleagues “began to hear on the grapevine that the paleoanthropological community was abuzz about our work — work that had never been presented anywhere.”