Buzz
In Madagascar, scientists uncovered the skeletal remains of a horned crocodile deep within a submerged cave. Barry ColemanThe Cooper River winds through the marshes of South Carolina, offering a rich ecosystem for both sportfish and shorebirds. This waterway begins in Berkeley County's Lake Moultrie, stretching down to Charleston, where it converges with the Ashley and Wando rivers to create the renowned harbor. (Are you familiar with Fort Sumter?)
The Cooper River was named after Anthony Ashley Cooper, a 17th-century English nobleman. Over the centuries, it played a vital role in the region's growing rice trade. Yet, it also carries the legacy of a much older chapter in South Carolina's history.
If you know where to search, and have your scuba equipment ready, you may just stumble upon a mammoth tusk hidden beneath the water's surface.
Matthew Weas is all too familiar with that sensation. Together with his father, Joe Harvey, they are seasoned divers who explore the Cooper River for fossils — many of which are later showcased at the Berkeley County Museum in Moncks Corner, South Carolina.
Not every giant they encounter is from the past. According to Weas, encounters with living river creatures are quite frequent. "I've had a [catfish] swallow my hand in an underwater log jam, a [manatee] emerge while I was swimming back to the boat... [and] alligators swim straight at me," he recalls via email. On one occasion, he was face-to-face with a 10-foot (3-meter) alligator.
This skull belonged to an extinct lemur that was once part of Madagascar's primate community, which vanished within the last 1,100 years.
Barry ColemanThe Cave of Wonders
Though the American alligator is strongly associated with the southern United States, the thrill of diving for ancient fossils extends beyond the country’s borders. Divers across the world—from Australia to Bali, Brazil, Indonesia, Mexico, and the Bahamas—have unearthed prehistoric treasures.
In 2014, a genuine 'lemur graveyard' was uncovered within the submerged caves of Madagascar's Tsimanampetsotsa National Park. This remarkable discovery came about through the teamwork of anthropologists, paleontologists, and skilled scuba divers from around the globe.
Amidst the underwater sediment, hundreds of bones were uncovered. While some belonged to present-day species, like the invasive black rat, others originated from creatures that vanished in the recent millennia.
The site quickly became known as the largest collection of Pachylemur fossils ever found. This ancient relative of the ruffed lemur weighed roughly 22 pounds (10 kilograms), making it twice the size of its modern counterpart. Even so, it was dwarfed by the massive Mesopropithecus, a lemur of gargantuan proportions also found in the caves.
The dive team also recovered remains of a pygmy hippo, the colossal elephant bird, and a horned crocodile, in addition to the rare, nearly intact skull of another long-extinct lemur species.
Accessing these fossil treasures was no simple task. While the caves were likely dry at some point in history, they are now submerged in a flooded sinkhole. The cave with the richest fossil deposits plunges 82 feet (25 meters) into the murky depths, featuring a labyrinth of horizontal corridors and dark waters.
To summarize, this was no place for inexperienced divers. Cave diving, in general, is a perilous activity; without a clear path, divers cannot always surface straight up. To ensure they didn't lose their way, the expert divers on the 2014 team laid down around 879 feet (268 meters) of safety lines to track their journey.
This 30-inch section of Mastodon tusk was recovered during a dive in the Cooper River, South Carolina.
Joe HarveyThe Importance of Preparation
Another significant site is the Page-Ladson sinkhole, located in northwestern Florida beneath the Aucilla River. This site has revealed some of North America's earliest-known human artifacts. Equally captivating are the mastodon bones found here, some dating back 14,550 years, marked with scars indicating they were butchered by ancient Floridians.
At this location, tannins prove to be quite a challenge. These chemical compounds, released by various plants, are an essential part of leather production. When tannins enter ponds or rivers, they discolor the water, turning it a brownish-black. This makes it difficult to see clearly. In certain sections of the Aucilla River, tannins block sunlight, casting an eerie, inky darkness over everything deeper than 10 feet (3 meters).
In the Cooper River further north, divers face a similar issue. To navigate the murky waters, they — along with their colleagues from Aucilla — rely on powerful underwater lights to enhance their visibility.
Weas mentions that he and his father wear Dive-Rite "cave lights" attached to their helmets. Their other gear is typical of recreational divers. 'We use the standard tank, regulators, and BCDs,' Weas explains. (For clarity, BCD stands for 'Buoyancy Compensating Device,' a piece of equipment used to maintain the diver’s desired depth.)
During summer dives, Weas and Harvey can easily wear pants and T-shirts. However, under certain weather conditions, they might opt for dry suits, semi-dry suits, or wetsuits. Given the strong tidal currents in the Cooper River, the speed of the water at any given moment influences their dive schedules. Faster currents result in shorter dives.
This collection from a Cooper River dive includes multiple shark's teeth alongside a brass Colonial belt buckle.
Joe HarveyGiant Sharks ... And Beavers?!
Why do divers go to such lengths when there are plenty of fossils on dry land? One reason is that immersion in water provides certain preservation benefits. When bones are deep inside a submerged cave, they are less likely to be disturbed, whether by scavengers or the unpredictable conditions of the open air.
While fossils found on land are often encrusted in rock, some bones discovered in flowing rivers are polished smooth by the constant motion of the water.
Weas uncovers materials in the Cooper River that span two distinct geological periods. Among the most prized fossils are shark teeth from the Miocene Epoch, which occurred between 23 million and 5.3 million years ago. Some of these teeth grow to impressive sizes: The tooth of the extinct megalodon shark can reach a length of up to 7.6 inches (19.3 centimeters)!
"Shark teeth are by far the most frequent finds," Weas notes, "but whale ear bones come in a close second."
Other fossils in the Cooper River date back to the Pleistocene Epoch, which began 2.6 million years ago and ended just 11,700 years ago. During this time, the sea levels were lower, and the Carolina coastline extended farther east.
Over the years, Weas and Harvey have uncovered the bones of Pleistocene mammoths, capybaras, large herbivorous hoofed animals, and even giant beavers. To explain this last one: During the Ice Age, North American wetlands were inhabited by Castoroides, enormous 8-foot (2.5-meter) beavers that likely weighed around 220 pounds (100 kilograms) or more.
It's undoubtedly unsettling to have a manatee approach you unexpectedly. But just imagine swimming alongside one of those giant rodents! No thanks, I'll pass.
As recently as 8,200 years ago, Great Britain was still connected to mainland Europe. This is why mammoth bones are sometimes dredged up from the North Sea, which separates the U.K. from its European neighbors.
