Study of 386 Fossils Finds Homo Body Size Jumped 2 Million Years Ago

3 articles · Updated · Sci.News · Jun 22

A University of Reading-led study found the biggest hominin body-size shift came about 2 to 2.5 million years ago within later Homo, not through steady growth across the entire lineage.
Researchers analyzed body-mass estimates from 386 fossil specimens covering 21 species and tested competing evolutionary models that accounted for how those species were related.
Homo erectus and Homo ergaster emerged as the first hominins averaging about 60 kg or more, while earlier Australopithecus averaged roughly 40 kg and remained much smaller.
Homo floresiensis and Homo naledi stayed well below expected body mass for their eras, reinforcing the study's conclusion that human evolution did not follow a simple, uniform growth path.
Published in PNAS, the findings tie the later size leap to broader shifts in bipedality, carnivory and environmental range, challenging a decades-old model of gradual enlargement.

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Sci.News2d ago

New Study Challenges Hominin Body Size Evolution Model, Finds Jump in Later Homo

MSN2d ago

Study finds sudden body size leap in early humans

Facebook2d ago

Hominin body size evolution is a complex process

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Rethinking Human Evolution: The Surprising Body Size Shift in Homo 2 Million Years Ago

Overview

A groundbreaking 2026 study by Jacob Gardner and colleagues has transformed our understanding of human evolution. Instead of a simple, steady increase in body size, the research reveals that hominin evolution followed a more complex path, marked by a major, lineage-specific size shift within the genus Homo. This challenges the old idea of constant growth and shows that different hominin branches evolved in their own ways, with earlier species like Australopithecus staying small for long periods. The study’s advanced methods highlight that our ancestors’ journey was shaped by sudden leaps, not just gradual changes.

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