New hand fossils rewrite a chapter of human evolution — and surprise scientists

Two nearly complete fossil hands unearthed in East Africa are forcing researchers to rethink how our ancient relatives used their hands — and what that means for the evolution of tool use, climbing and manual dexterity.

Photo Disclosure By Louise Leakey

The specimens, attributed to an extinct early human relative, reveal a surprising mix of features: a grip strong enough for powerful clamping and climbing, yet with anatomical traits that suggest finer, more human-like manipulation than expected for a species long seen as primarily adapted to arboreal life. The result is a more complex picture of how hands evolved into instruments of both locomotion and craftsmanship.

A hand that does two jobs

Paleontologists have long assumed a fairly simple trade-off in early hominins: hands built for climbing trees lacked the subtle anatomy needed for precision grips, and vice versa. The new fossils — described in a Stony Brook University–led study and analyzed alongside comparative material — break that tidy dichotomy. One of the recovered hand skeletons shows robust metacarpals and finger bone proportions associated with strong, power grips (useful for climbing and forceful hold), while wrist and thumb features point toward the ability to oppose the thumb and manipulate objects with more finesse.

“This is what makes these finds so exciting,” a member of the research team told the press: the hands combine gorilla-like strength with unexpectedly human-like dexterity, suggesting these hominins could both climb effectively and perform tasks requiring refined manipulation.

Who owned these hands?

The fossils have been linked to Paranthropus boisei — a robust East African hominin that lived roughly 1.5 million years ago. Paranthropus has often been framed as an evolutionary side branch adapted to heavy chewing and a predominantly terrestrial life. These new hand bones complicate that story, indicating a behavioral flexibility that could include climbing, food processing, and even rudimentary tool use.

Researchers point out that morphology alone cannot prove the presence of systematic tool manufacture, but the anatomical evidence increases the plausibility that Paranthropus and similar species had the manual capacity to manipulate objects in ways previously reserved for lineages more directly tied to Homo. In short: capability does not equal evidence of frequent tool production, but it does expand what’s possible in behavioral reconstructions.

Rethinking the evolution of the human hand

The new data support a growing consensus among anatomists and paleoanthropologists that the evolution of the hand was not a linear march from “tree-climber” to “tool-maker.” Instead, the fossil record increasingly shows a mosaic of forms and functions: different species experimenting with combinations of strength and precision as they adapted to varied environments and lifestyles. That mosaic view helps explain how some hominins might have retained arboreal abilities while also exploiting new ecological niches that favored object manipulation.

Max Planck researchers and collaborators have framed the finding as evidence that “our fossil ancestors had different ways of ‘getting a grip,’” stressing that ancient hands evolved multiple strategies for interacting with the world rather than following a single blueprint.

What this means for human origins

Beyond technical anatomy, the discovery matters because hands are the physical interface between cognition and action. A hand capable of both powerful grips and refined manipulation widens the range of behaviors a species could perform — from climbing and foraging to shaping food items and using simple tools. Those behaviors, in turn, influence diet, mobility and even social learning, all key elements in narratives about human evolution.

Scientists caution that more evidence is needed: additional fossils, contextual finds (stone tools, cut-marked bones), and rigorous biomechanical modeling will help determine whether these hand anatomies mapped onto routine behaviors or sporadic, opportunistic acts. Until then, the hands stand as a provocative reminder that evolutionary change is often inventive and multi-threaded.