Space and Science

Early humans used bows and arrows to hunt in tropical rainforests 48,000 years ago, study says

CNN  — 

Early humans living on the island of Sri Lanka 48,000 years ago crafted tools from animal bones and used them to hunt monkeys and squirrels, according to a new study. This represents the earliest evidence of bow and arrow technology outside of Africa to date.

Last year, researchers released a study analyzing monkey and squirrel bones found in the Fa-Hien Lena cave on the island; the research revealed that early humans hunted them. This cave is also the site of the earliest fossil appearance of Homo sapiens in South Asia. Humans occupied the area during four different time periods between 4,000 and 48,000 years ago.

Some of the bones in the cave had been fashioned into tools, so the researchers analyzed them to understand how our early ancestors managed to successfully hunt such quick-moving small animals in the rainforest.

Beneath a microscope, the tools revealed the story.

“The fractures on the points indicate damage through high-powered impact — something usually seen in the use of bow-and-arrow hunting of animals,” said Michelle Langley, lead study author and senior lecturer of forensics and archaeology at Griffith University, in a statement. “This evidence is earlier than similar findings in Southeast Asia 32,000 years ago.”

The study published Friday in the journal Science Advances.

This discovery predates evidence of bow and arrow technology found in Europe around 20,000 years ago, said Patrick Roberts, the study’s co-author and group leader of the stable isotope laboratory in the department of archaeology at the Max Planck Institute for the Science of Human History.

Some researchers have suggested that the technology arrived earlier in Europe. But Roberts, who is also a senior research fellow in the University of Queensland’s School of Social Science, said “this remains hotly debated.”

“The earliest clear evidence anywhere in the world is currently 64,000 years ago in South Africa,” Roberts said.

After the initial invention of this technology in Africa, it was reinvented and reused across different regions and habitats across time, he said.

“Humans did not ‘invent’ technologies like this once, but rather different populations developed and adapted them repeatedly to unique contexts,” Roberts said. “Instead of bow and arrow being homogeneously linked to one environment, they are just part of the human ‘toolkit’ that enabled our species to flexibly adapt to almost all of the environments the planet had to offer during the Late Pleistocene [129,000 to 11,700 years ago].”

While the tools were likely used initially to hunt monkeys and squirrels, longer tools and the bones from deer and pigs have revealed that they adapted to hunt larger animals.

Unique beads

In addition to the stone tools, the researchers uncovered beads made from shell, shark teeth and the oldest known beads made entirely from ocher. The marine shells and shark teeth can be traced to the coast, although the people who wore them lived in the rainforest. They estimated that the beads are likely 45,000 years old.

The shell beads, as well as different pigments in bright red, yellow, and silver, were used for personal ornamentation.

The researchers believed they were actually trading goods with other populations living along Sri Lanka’s coast. This means that they developed social networks in the tropics of South Asia.

“These networks would be key to survival, as if climate change or other issues faced one population they could be supported by another, allowing our species as a whole to persist and thrive,” Roberts said.

The beads represent early symbolism — something often associated with archaeological sites in Africa, Southeast Asia and Europe where ancient humans left evidence of personal ornamentation.

The researchers also uncovered evidence of awls made from bone, as well as scrapers, which could have been used to make clothing from animals skins or fishing nets from plants.

Previously, tools like this discovered at other sites have suggested that people developed this innovative tool to help them make clothing to adapt to their environment, like colder climates.

“In this case, perhaps [it offered] protection against mosquitoes and other tropical hazards,” Roberts said.

Spotlight on Sri Lanka

This study and other research is highlighting the importance of understanding where humans lived and evolved “beyond the traditional heartlands of paleoanthropological and Paleolithic archaeological research” in Europe and coastal Africa, Roberts said.

“The current paleoenvironmental evidence suggests that our species managed to occupy not just tropical rainforests, but also high altitude, desert and paleoarctic environments during the Late Pleistocene,” Roberts continued. “Many of these ‘extreme’ environments have often been considered unattractive for archaeological research, due to the likelihood of not finding clear traces of human behaviour; difficult working conditions; and, in some cases, preservation issues.”

However, the researchers were surprised to find such great evidence in the cave that is affording so much insight into how these ancient humans lived. Not only did humans live in African savannas, grasslands and woodlands, but they adapted to thrive in extreme settings like rainforests as well.

“What this work shows, as well as emerging work across these environments in the last two decades, is that these should be key sites for investigation, whether it is the rainforests of Africa, Southeast Asia, or New Guinea or the mountains of the Himalaya, the Ethiopian Highlands and Lesotho,” Roberts said.

Currently, the research team is exploring coastal sites in Sri Lanka to find evidence of other early human inhabitants — perhaps those who traded shell beads with the rainforest-dwelling early humans. It might shed light on what they received from the trade.

“Humans at this time show extraordinary resourcefulness and the ability to exploit a range of new environments,” said Nicole Boivin, study co-author and director at the Max Planck Institute for the Science of Human History, in a statement. “These skills enabled them to colonize nearly all of the planet’s continents by about 10,000 years ago, setting us clearly on the path to being the global species we are today.”