Ancient Peruvians Never Adopted the Bow, Study Finds

Rising population, increasing violence, and easy access to high-quality raw material: these are exactly the conditions researchers expect to push a society toward inventing the bow. In one part of ancient Peru, none of that happened.

Testing an Assumption About Weapons

A new study published in the Journal of Archaeological Method and Theory examined weapon technology among Paracas communities in the Palpa valleys of southern Peru during the Final Formative period, roughly 400 to 1 BC. Researchers led by Erik J. Marsh set out to test a common archaeological assumption: that new weapons like the bow tend to emerge alongside growing populations and rising conflict, since bows generally offer better accuracy, range, and firing speed than earlier projectile technology.

Two Hundred Points, All the Same Answer

The team reviewed 406 stone artifacts from five archaeological sites, ultimately narrowing the sample to 200 well-preserved obsidian projectile points. Using Bayesian statistical models that compared each point’s width and thickness against archaeological examples confidently linked to bows or spearthrowers, researchers classified every single one of the 122 most complete points as spearthrower darts, with median probabilities between 95 and 99 percent. Even damaged or heavily reworked points followed the same pattern. Burials backed this up directly: Paracas male graves contained spearthrowers, slings, obsidian knives, stone mace heads, and hide-covered shields, but never a bow. Textiles depicting armed men showed the same weapons, and a spearthrower hook recovered at the site of Collanco confirmed the technology was actively in use.

A Society Built for Trade and Hunting

The chronology ruled out a short-lived local quirk. Researchers dated the Paracas occupation at Jauranga to roughly 460 to 250 BC and at the highland site of Cutamalla to about 240 to 40 BC, with most of the study’s projectile points coming from Cutamalla. Nearly all of the obsidian used in the region traced back to the Quispisisa source 63 kilometers away, almost certainly moved by llama caravans, showing these communities were well connected rather than isolated or short of raw material.

Violence Without a New Weapon

The broader historical backdrop makes the pattern harder to dismiss. During the Final Formative, coastal Peru experienced what researchers describe as the Andes’ first large-scale horizon of warfare. Adult cranial trauma reached about 31 percent across the coastal sample the researchers reviewed, and at Paracas Cavernas specifically, 40 percent of 124 adults showed evidence of skull trauma. The study compiled 53 sites in the Palpa valleys with walls, weapons, or defensible positions, though the researchers describe the evidence there as more consistent with small-scale raiding than sustained large-scale war.

Why Change a System That Worked?

Researchers suggest a mix of practical reasons explains the pattern. Spearthrowers suited the open terrain of southern Peru, and their heavy darts delivered strong stopping power against deer and wild camelids, the region’s most valuable prey. Slings, simple to make from wool, hide, and stone, could be used one-handed and remained part of Andean warfare for centuries afterward. Locally available woods were often too stiff or knotty for efficient bows, and established weapon traditions may have simply left little pressure to switch. The researchers note that the same puzzling absence may extend to later Nasca, Moche, and Chimú cultures, raising broader questions about what actually drives a society to adopt new weapons technology.

Sources

This report draws on the peer-reviewed, open-access study published in the Journal of Archaeological Method and Theory by Marsh, Yebra, Castro, and colleagues.