The largest hoard of Viking Age silver ever found in Finland — which contains almost 10 pounds (4.5 kilograms) of coins and jewelry — has been unearthed by a metal detectorist about 95 miles (150 kilometers) north of Helsinki.

The hoard had been divided into two deposits and buried in birch-bark containers. Although the coins and jewelry likely date to between A.D. 1000 and 1050, it's unknown exactly when they were buried, Esko Tikkala, an archaeologist at the Lahti Historical Museum who excavated the hoard, told Live Science in an email.

The hoard has not yet been fully cleaned, separated and counted yet, but there are thousands of pieces, Tikkala said. "There are quite a lot of coins in this hoard," he said. "I have not had time to go through them."

Metal detectorist Kalle Lappinen found the two deposits Sept. 3 and immediately contacted the museum. Archaeologists inspected and properly excavated the finds the next day, according to a translated statement.

Tikkala described the hoard site as beside a rock outcrop in a forest near the town of Sysmä. Several other buried hoards had been found in the same region of Finland over the past 10 years, Tikkala said.

Although it's challenging to determine why specific hoards were buried, a recent study of more than 15,000 Roman-era (the eighth century B.C. to the fifth century A.D.) hoards found that they were hidden for multiple reasons, including for tax evasion, votive offerings, and safe storage in times of uncertainty.

Tikkala said the two deposits of the silver hoard were buried between two stones about 18 inches (45 centimeters) below ground and about 39 feet (12 meters) apart. There were no signs of any burials nearby, but the surrounding area had not been properly studied, he said.

Tikkala added that the coins came from areas that corresponded to present-day Germany, Sweden and Great Britain. There were also some dirhams —‬ silver coins made in the Islamic world. Dirhams previously found in Finland generally date to between about 800 and 1050, he said.

The hoard also contains several pieces of jewelry, including a silver bracelet, and "payment silver" in the form of hack silver (also called hacksilber) — pieces of silver that could be cut into smaller pieces for payments according to their weight.

The weight of the precious metal alone would make the hoard worth almost $10,000 today.

From the Viking Age, but not from Vikings

Although the hoard is from the Viking Age (traditionally, from the 793 attack on Lindisfarne until the 1066 defeat of a Viking army at Stamford Bridge in England), that doesn't mean it was buried by Vikings, Tikkala said.

"The term Viking Age does not imply that there were Vikings in Finland," he said. "We have no sources suggesting that Finland was 'Viking' in the same sense as regions of present-day Sweden, Norway, and Denmark."

Instead, Finnish historians and archaeologists had adopted the term to designate the period, he said. But the area now known as Finland was not culturally or politically part of Viking Scandinavia.

The next stage of the archaeological investigation will be to properly study the site where the two deposits were found, as well as their surroundings, Tikkala said; after that, specialists in Viking Age coins will try to identify the coins and prepare a detailed report.

"There will definitely be scientific articles published on the hoard as a whole, as well as more detailed studies of the coins themselves," he said.

Until now, Finland's largest Viking Age hoard was found in 1895. Buried at Nousiainen, about 130 miles (210 km) southwest of Sysmä, it contained more than 1,700 silver coins but weighed only about half as much as the newfound hoard.

Other Nordic countries have also recently reported their largest Viking Age hoards. A cache of more than 4,700 coins was found in Norway this past spring, and a homeowner in Denmark unexpectedly discovered a hoard of more than 700 silver objects weighing more than 40 pounds (18.5 kg) in their backyard, also in the spring.

See how much you know about ancient norsemen with our Viking quiz!

The world's oldest known habitual drug use can be traced to an island in Indonesia, where ice age hunter-gatherers sucked on betel nuts — palm seeds that contain a neuroactive substance, a new study finds.

Scientists made the discovery after studying strange grooves in the teeth of two prehistoric hunter-gatherers. The deep grooves were caused by regularly sucking on betel nuts (Areca catechu), likely for relief from the pain of toothache, according to the study, which was published Wednesday (Sept. 9) in the journal Science Advances.

The partial skeletons of the two people were found on the island of Sulawesi, but their lives were separated in time by thousands of years. One of them, a man who died between about the ages of 40 and 50, lived between 25,000 and 16,000 years ago. This period roughly corresponds to the Last Glacial Maximum, the coldest part of the last ice age — although Sulawesi was not covered with ice at that time. The second person, who was around the same age when they died, lived on Sulawesi between 7,600 and 6,300 years ago, according to the study. The sex of this individual could not be determined.

Betel nuts contain a neuroactive compound called arecoline, which has a powerful stimulant effect when chewed with slaked lime, or calcium hydroxide. This early method of directly sucking betel nuts, however, would have only made the mouth numb.

These hunter-gatherers had so much dental damage, the new analysis found that they must have sucked on betel nuts almost continuously throughout their lives. But it seems these numbing nuts didn't have the desired effect in the long run. Instead, it may have made their dental conditions worse by eventually exacerbating any painful holes in their teeth.

"The more they sucked on the nut to relieve toothache, the worse that the damage to their teeth became," study first author Adam Brumm, an archaeologist at Griffith University in Australia, told Live Science. The grooves progressively became deeper, and in one individual they exposed the tooth's inner pulp cavity. "It would have been excruciatingly painful," Brumm said.

Although a 2017 study showed that Neanderthals used the bark of plants like poplar (genus Populus) for its pain-killing properties (poplars contain salicylic acid, a form of the active ingredient in aspirin), this is the earliest evidence of a drug from plants being used habitually, Brumm said.

Plant-based drugs have been used in many other prehistoric societies: 10,000-year-old traces of the pollen of a psychedelic cactus have been found in Peru, and 13,000-year-old residues of alcoholic beer have been found in Israel.

Addictive nut

After determining the likely cause of the grooves, the researchers tested whether sucking on betel nuts — a behavior not seen before — resulted in a neuroactive effect. Their test subjects, genetically-engineered frog eggs with human neuroreceptors, revealed there was a neuroactive effect. Then, they examined samples from the teeth, which revealed traces of betel nut use.

Betel nut, also known as areca nut, is still widely used today in parts of South Asia and Oceania. Today, however, betel nut users mix it with slaked lime to make a chewable wad that has a stimulant effect. This chewable wad, also called a quid, is strongly addictive, and is used by an estimated 600 million people worldwide. But arecoline is also carcinogenic, and betel nut quids are often mixed with tobacco, so users are often diagnosed with mouth cancer.

The researchers speculate that the use of slaked lime with betel nuts originated much later, during the Neolithic, or "New Stone" Age, about 4,000 years ago on Sulawesi, when slaked lime was added to pottery to prevent it from shrinking and cracking during firing.

"It now seems probable that betel chewing as we know it evolved from a much simpler, older practice of just sucking on the intact nut," the researchers wrote in the new study.

It's likely that people of all ages used this remedy for toothache in prehistoric times, but the grooves only became apparent in mature people who had become addicted to the practice, Brumm said.

Drug use started before farming

The earlier betel-sucking man predated the Neolithic period not only in Sulawesi but also in the Fertile Crescent, where people began practicing agriculture around 12,500 years ago, Brumm said. Archaeologists have long debated whether people began using neuroactive plants as drugs before or after the introduction of farming, but the new finding shows that psychoactive drug use happened thousands of years earlier, Brumm said.

The new study is a "fantastic piece of research," Elisa Guerra Doce, a prehistoric archaeologist at the University of Valladolid in Spain who was not involved, told Live Science in an email.

The new study gives "particularly compelling and direct evidence for the antiquity of drug use," she said.

Guerra Doce is an expert on the prehistoric use of plants as neuroactive drugs. "In the specific case of betel nuts, the findings are especially significant because they also reveal the prehistoric roots of a deeply established cultural practice in Southeast Asia and the Pacific," she said.

The study also highlights how the prehistoric people of Sulawesi explored their natural world and figured out that it not only provided subsistence and medicinal resources but also had "substances that became integrated into social and cultural traditions over thousands of years," Guerra Doce said.

Archaeologists excavating in southwestern China have discovered a cave that was used by Denisovans for more than 100,000 years. Five human fossils, scores of stone tools, and hundreds of animal bones recovered from the cave reveal for the first time that the enigmatic Denisovans thrived in a forested environment where they hunted and ate large game animals.

Denisovans were a lineage of humans who lived in Asia and went extinct around 30,000 years ago. Ancient DNA has shown that Denisovans, Neanderthals and modern humans (Homo sapiens) are distantly related and that all three groups interbred in the past. But while archaeologists have found numerous Neanderthal and modern-human skeletons, Denisovans are known from only a handful of fragmentary fossils scattered from Siberia to Laos. This lack of evidence has severely limited experts' understanding of Denisovans' bodies and their culture.

In two studies published Wednesday (Sept. 9) in the journal Nature, researchers detailed their excavation of Bianfu Cave in southwestern China. Animal bones and ancient tools revealed that the cave was used from 190,000 to 70,000 years ago, and five human fossils dating to between 134,000 and 167,000 years ago confirmed that the people who used the cave were Denisovans.

Bianfu Cave is in the Yunnan province of southwestern China. In 2019, archaeologists excavated several stratigraphic layers of the cave and discovered nearly 1,400 stone artifacts, more than 64,000 mammal bones, and four teeth from an unknown human lineage. The Yunnan area is where Denisovans and modern humans are known to have met and mated, so researchers were unsure which group had used tools to butcher animals inside Bianfu Cave.

In one study, a research team used a technique called zooarchaeology by mass spectrometry (ZooMS) to quickly and efficiently screen the bone fragments from Bianfu Cave. ZooMS is a form of protein analysis that involves extracting collagen from the bones of an unknown species and comparing the protein pattern to the unique "fingerprint" of reference animals.

When the researchers applied the ZooMS technique to the Bianfu Cave bones, they discovered that three of the fragments had a collagen pattern found in members of the Homo genus. Then, using proteomic analysis, the researchers found that two teeth and three bones from Bianfu Cave had a particular amino acid variation linking the fossil remains with Denisovans.

Denisovans are still poorly understood, in part because no complete skeleton has ever been found. Most of the Denisovan fossils that experts have studied are pieces of the skull and teeth. A tiny finger bone and a rib fragment were all that had been found of Denisovans' bodies before the Bianfu Cave excavation. But one of the three bones identified as Denisovan through ZooMS was a fragment of a radius, one of the paired bones in the forearm. It is the only Denisovan radius found to date.

The newly discovered radius has a large head (where it connects to the humerus at the elbow) that is more similar to those seen in Neanderthals than in modern humans, but its overall shape is more similar to modern-human radii, the researchers wrote in one of the new studies. The fact that the Denisovan radius was shaped more similarly to the radius in humans "likely provided functional advantages for lightweight, precise manipulation," study co-author Qiaomei Fu, director of the Ancient DNA Laboratory at the Institute of Vertebrate Paleontology and Paleoanthropology, part of the Chinese Academy of Sciences, in Beijing, told Live Science in an email.

The unique features of the Denisovan radius also suggests that the Denisovans living near Bianfu Cave had different biomechanical demands on their bodies and different behavioral adaptations, the researchers noted.

Denisovan stone and bone tools

In a related study, researchers looked at the entire cultural sequence from Bianfu Cave to work out what Denisovans were doing there.

Of the nearly 1,400 stone artifacts recovered from the cave, there were about 200 flake tools, many of which were made from a sedimentary rock called sandy mudstone. These tools left marks on a number of animal bones discovered in the cave, suggesting that Denisovans regularly hunted, butchered and extracted marrow from cow- and deer-like animals, the researchers wrote in the study.

But the stone tools found at Bianfu Cave are different from the more sophisticated ones that Neanderthals made around the same time. The Denisovan stone tools appear to have been crafted quickly and efficiently from locally available materials, according to the study. The researchers, however, discovered that Denisovans at Bianfu Cave were also making bone tools, which Neanderthals did as well. This suggests that bone tool use may have been more widespread among Pleistocene human groups than experts previously thought, the researchers wrote, and it highlights the need to better understand the human evolutionary record of eastern Asia.

Although the studies have contributed new information to archaeologists' understanding of the enigmatic Denisovans, more work needs to be done, according to the researchers.

"We hope that similar proteomic analyses will aid in the identification of further Denisovan long bones in the future," Huiyun Rao, an associate professor at the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, and colleagues wrote, "to further understand the adaptive behavior of Denisovans in response to climate change or competitive pressure from contemporary hominins."

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