CAMBRIDGE, Mass., March 17 (UPI) -- Prehistorians believe the transition from dense, elevated forest to flat, open grasslands in East Africa spurred humans' ancestors to first abandon all fours and walk upright. But when exactly did this happen? Researchers say a long lost beaked whale fossil may offer clues.
Though the beaked whale fossil in question is only just now making headlines, it was first discovered in Kenya in 1964. It was unearthed some 460 miles inland, suggesting the sea mammal had gotten lost and swam up a freshwater river system. But the 17-million-year-old fossil was originally misidentified as a turtle, and little analysis was conducted before it went missing.
It stayed lost in the archives of Harvard University for nearly 40 years, before Louis Jacobs -- who knew of its existence but for years failed to locate the fossil -- finally found the skull.
While the whale's journey inland is fascinating in itself, the fossil's rediscovery has offered much grander scientific revelations. The skull has helped researchers to date the East African plateau's uplift, and thus allowed scientists to more accurately pinpoint the place and time when human bipedalism first emerged.
"The whale is telling us all kinds of things," study co-author Louis Jacobs, a paleontologist at Southern Methodist University in Dallas, told the Los Angeles Times. "It tells us the starting point for all that uplift that changed the climate that led to humans. It's amazing."
To date and measure the plateau's uplift, scientists used the original field notes to relocate the site of fossil's initial discovery. Next researchers looked at evidence of modern whales and dolphins who became lost upriver. Because they knew whales could only travel up a wide, low-gradient river, scientists were able to estimate the nature of the ancient waterway. Their analysis suggested the original site of whale's death (likely from exhaustion) couldn't have been more than 372 to 559 miles from the Indian Ocean and nor more than 78 to 121 feet high.
Today, that same spot is more than 2,000 feet above sea level, meaning uplifting forces from a plume of magma in the Earth's mantle has caused some 1,935 feet of rise in the 17 million years since the whale's fateful end.
"At the time when the whale stranded, it was assumed that there was a pan-African rainforest across the entire area," lead study author Henry Wichura, a geoscientist at the University of Potsdam, in Germany, told Australia's ABC Science.
Wichura is an expert on the plateau's uplift and ancient climate change in East Africa. But a more accurate date on the start of East Africa's uplifting suggests the transition from forest to grasslands began sooner than previously thought -- the climate change that first made walking on two feet advantageous.
"Even single specimens of organisms tell us a great deal about the history of the Earth, and they sometimes appear in surprising cases," Frank Brown, a geologist at the University of Utah who was not involved in the study, told Live Science. "This is one such case."
The new study was published in the journal PNAS this week.