Earliest known open-ocean fishing hooks found in East Timor

Story: ~40,000 B.C.E.  |  Last updated: January 10, 0001

On the eastern tip of a small island north of Australia, someone shaped a sea snail shell into a careful curve and dropped a line into deep water. The fish hooks recovered from Jerimalai Cave in East Timor are the oldest confirmed fishing hooks ever discovered — and the bones piled beside them are not from shallow-water species. These people were working the open ocean, tens of thousands of years before the first cities were built.

Key findings

• Open-ocean fishing hooks: Shell hooks carved from Trochus sea snails were recovered from Jerimalai, a limestone rock shelter on the eastern tip of Timor, with the oldest confirmed hooks dated to between 23,000 and 16,000 B.C.E. — the earliest known fishing hooks in the world.
• Deep-water fish bones: Bones of tuna and giant trevally — fast, pelagic species that live well offshore — were found in the same deposit, with evidence of fishing activity extending back to approximately 42,000 B.C.E., suggesting hooks or nets were in use long before the recovered hooks themselves.
• Maritime technology: The combination of manufactured hooks, offshore target species, and an island location implies these people had functional watercraft, navigational knowledge, and a sophisticated understanding of ocean ecology tens of thousands of years before the earliest known civilizations.

A limestone shelter that rewrote fishing history

Archaeologist Sue O’Connor of the Australian National University discovered Jerimalai Cave in 2005 C.E., initially expecting little. What her team found over subsequent excavations — published in the journal Science in 2011 C.E. — pushed back the known origins of fishing technology by a staggering margin.

The hooks were shaped from Trochus shells, small spiral mollusks still common across the Indo-Pacific today. Each one was deliberately ground into a precise curve. These were not accidental forms. They were manufactured tools, produced through a multi-step process: selecting the right shell, understanding its structural properties, grinding without snapping, and shaping a finished object that existed in the maker’s mind before it existed in the world.

That last part matters. The ability to plan a sequence of steps toward an unseen result is one of the markers researchers use to identify modern cognitive behavior. The people at Jerimalai had it. They were also using it to catch tuna — one of the fastest, most evasive fish in the ocean, which does not come near the shore.

In one square-meter pit, just two meters deep, O’Connor’s team recovered 39,000 fish bones. The site had been used, returned to, and used again across thousands of years.

What open-ocean fishing required

Catching tuna and giant trevally is not a shoreline activity. These species live in fast, open water. Reaching them required boats capable of handling ocean swells, knowledge of where the fish could be found, and either hooks on long trolling lines or nets deployed from moving vessels.

O’Connor noted that simple fish aggregating devices — tethered logs that attract pelagic species — were likely also part of the picture. But any of these methods required the same underlying capability: intentional offshore travel, coordinated effort, and the kind of ecological knowledge that only builds across generations.

The island of Timor sits between Southeast Asia and Australia. Reaching it at all — whether from the Asian mainland or from Sahul, the ancient landmass that included Australia and New Guinea — required open-water crossings of at least 90 kilometers even during periods of lower sea levels. The people who lived at Jerimalai were not accidental arrivals. They were ocean-capable by necessity, and they refined that capability into something remarkable.

As O’Connor put it: “Early modern humans in island Southeast Asia had amazingly advanced maritime skills. They were expert at catching the types of fish that would be challenging even today.”

Lasting impact

The Jerimalai find has reshaped how researchers think about the cognitive and technological capabilities of early modern humans in Southeast Asia and the Pacific. For decades, the assumption was that deep-sea fishing emerged relatively late — perhaps 10,000 to 15,000 years ago. Jerimalai moved that date back by 30,000 years or more.

The implications extend beyond fishing. If people in this region had sophisticated watercraft and navigational knowledge by at least 42,000 B.C.E., it helps explain one of prehistory’s great open questions: how modern humans reached Australia by at least 65,000 B.C.E., crossing open ocean with no land bridge available. The skills visible at Jerimalai were not a local curiosity — they were part of a broader maritime capability that allowed humans to populate one of the most isolated continents on Earth.

The Trochus shell hooks also foreshadow a technology that would become universal. Hook-and-line fishing remains one of the most widespread food-gathering methods in the world today, practiced from the Arctic to the tropics. Its roots, it turns out, run deeper than almost anyone expected.

The Jerimalai site also sits within a broader cluster of significant archaeological caves along East Timor’s eastern coast. Nearby Lene Hara Cave contains hand stencil rock art potentially dating to the same Pleistocene period. The region was clearly a place of sustained, rich human activity — not an isolated outpost, but a living community at the edge of the ocean.

This corner of Southeast Asia has increasingly become central to understanding how modern humans spread across the planet. Research on ancient DNA from island Southeast Asia has traced complex patterns of migration and mixing that complicate earlier, simpler models of human dispersal. Jerimalai is one data point in a much larger and still-unfolding story.

Blindspots and limits

The record from Jerimalai is extraordinary, but it is also incomplete. O’Connor’s team had excavated only two small test pits at the time of the 2011 C.E. publication — a tiny fraction of what the cave may still hold. It is possible that older hooks exist in unexcavated layers, or at nearby sites like Matja Kuru, which has also yielded Pleistocene-era marine resources.

The 42,000 B.C.E. date applies to fish bones and human occupation at the site, not to the hooks themselves, which date to approximately 23,000–16,000 B.C.E. Whether hooks were in use earlier — and simply haven’t survived, or haven’t yet been found — remains an open question. Organic materials like wood, bone, and plant fiber decay quickly in tropical climates, which means the archaeological record almost certainly undercounts the full range of fishing technologies these people had.

And almost nothing is known about the specific people who made these tools: their social structures, their languages, their knowledge systems, or how fishing knowledge was transmitted across generations. The bones and hooks survive. The rest is silence — and ongoing excavation.

Read more

For more on this story, see: Facts and Details — Jerimalai Cave and early East Timor archaeology

For more from Good News for Humankind, see:

• Ghana establishes a marine protected area at Cape Three Points
• Indigenous land rights: 160 million hectares recognized ahead of COP30
• The Good News for Humankind archive on prehistory

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