For more than 100,000 years, the earliest humans hunted Pleistocene megafauna with wooden throwing spears. But by at least 64,000 years ago, people in Africa had invented a deadly new way to hunt: the bow and arrow. Bows and arrows eventually became a staple of hunting and warfare for cultures on five continents, but we’re not sure exactly when or how that Paleolithic weapons proliferation took place.

Archaeologist Michelle Langley and her colleagues recently found an important clue in a Sri Lankan cave called Fa-Thien Lena: 130 bone arrowheads, dating to around 48,000 years ago. The discovery is the oldest evidence of bows and arrows ever found outside Africa. And it hints at how people adapted to survival in challenging new environments like the Arctic of Siberia, the high altitudes of Tibet, and tropical forests in Africa, Asia, and Melanesia. The invention of new technologies like this helped give Homo sapiens the edge we needed to conquer the world.

“There are a number of ways that bow-and-arrow technology could have got to Sri Lanka,” Griffith University Langley told Ars. “It could have been brought from Africa with a traveling population. It could have been independently innovated in Sri Lanka. Or it could have been innovated in Africa (or elsewhere) and then brought along trade routes or social networks by word of mouth or an example being brought along. At the moment, we have no idea which!”

Making important points

People seem to have lived at Fa-Thien Lena off and on since at least 48,000 years ago. The cave’s earliest residents left behind an assortment of bone tools, along with shell beads and the remains of ancient meals. They made and maintained their tools in the shelter of the cave; the excavation found partially finished tools and discarded debris buried in the cave floor. And those tools, flaked and ground from the limb bones of monkeys, are unlike anything archaeologists have found elsewhere.

“This Sri Lankan assemblage is unique for its time and the styles or types of tools (and ornamental pieces) found,” Langley told Ars. The bone arrowheads come in two types: some have one pointed end and one blunt end, while others have two pointed ends. Many of them show signs of impact damage, meaning they’d been fired at least once. “Such points made in bone with such clear indications of their use at this period are unknown outside of Africa (where it is stone points strongly suggested to have tipped arrows early on),” said Langley.

One of the points has two sets of short lines etched into its surface. They could be decoration or marks used to identify who owned the arrow, but they could also have been grooves for holding poison.

“Such short engraved lines are known from recent times to have been used to hold poison in place for hunting,” explained Langley. “We might be able to search for residues on this point for evidence of poison; however, this depends on how well the surface of the piece has preserved in this tropical context, what the soil was like that it rested in for thousands of years, what kind of poison may have been used, and how it was treated before being thrown away or lost in antiquity.”

Based on the size of the arrows and the collection of animal bones found scattered in the sediment of the cave floor, the earliest points probably brought down small prey like monkeys and squirrels. As time went on, the points got larger, and so did the animals that turned up among the cave-dwellers’ dinner leavings: wild pigs and deer. Bows and arrows would have been very useful for people who needed to hunt amid the dense vegetation of a tropical rainforest, where it would have been difficult to get enough clear space to throw a spear.

Survival takes more than just hunting

Bows and arrows were just one of the technologies that helped people survive. Langley and her colleagues suggested that some of the bone points may have been used as a form of hook for freshwater fishing (carp and catfish bones also turned up at the site) or as barbs in snares or net traps. Some of the points were definitely used for arrows, though; they have small notches to show where they’d have been hafted to arrow shafts about 1cm (0.4 in.) wide, and many also show signs of wear from hafting.

More surprising than the arrows, however, were another set of tools, including bone awls and leather-smoothing tools called lissoirs—the kinds of things you’d use to turn plant fibers or animal hides into useful things like clothes or nets. It’s hard to say what these were used for without more evidence, like rock art or a scrap of ancient netting. Anthropologist usually think of clothes as a cold-weather invention, but Langley and her colleagues say that some kinds of clothing could also have helped protect people from insect-borne diseases in the tropics.

“Neither clothing nor nets would surprise me greatly; they are both innovations which I could see being very useful in rainforest environments,” Langley told Ars. “The form they take (their design) would probably be the most surprising thing about them—hopefully we will find something that will give us insight into this in future fieldwork.”

Science Advances, 2020 DOI:
https://doi.org/10.1371/10.1126/eaba3831;(About DOIs).

https://arstechnica.com/?p=1683305