A new peer-reviewed study led by Ella Been at Ono Academic College provides rare insight into Neanderthal early life by examining the near-complete skeleton of Amud 7, a roughly 6-month-old infant from a cave near Israel's Sea of Galilee who lived 51,000–56,000 years ago. Using tooth eruption stage and microscopic analysis of dental enamel microstructure to establish dental age, combined with measurements of long-bone length and estimated cranial capacity for skeletal and brain development, the team found Amud 7's body and brain size matched a modern human toddler aged 12–14 months. The same accelerated somatic growth pattern appeared in two additional rare specimens: the 2-year-old Dederiyeh 1 from Syria and a 3-year-old from Roc de Marsal, France. With a total sample size of only three individuals, the researchers rightly caution that individual variation cannot be ruled out; these remains represent a tiny fraction of Neanderthal existence across Eurasia, and sex could not be determined.

This work, published in a specialist journal and distinct from any preprint, goes well beyond the straightforward size comparison covered by New Scientist. The original reporting notes faster early growth as likely adaptation to cold climates—larger bodies lose heat more slowly, per Bergmann's rule—but underplays the cascading evolutionary consequences. Synthesizing Been's data with Froehle et al. (2013) on Neanderthal energetics (American Journal of Human Biology) showing 10–20% higher daily caloric requirements than Homo sapiens, and Smith et al. (2010) on delayed Neanderthal dental maturation (PNAS), a clearer picture emerges: Neanderthals followed a high-investment, rapid-growth strategy in the first years of life that disappeared by age 7, after which trajectories aligned.

These differences reframe birth complications and hominin divergence. Delivering infants with such accelerated body and brain growth would have demanded even wider pelvic outlets than the already robust Neanderthal pelvis, elevating maternal and infant mortality risks in small, isolated bands. Modern humans' slower, neurologically plastic infancy may have allowed greater cultural learning time at lower immediate caloric cost, offering demographic resilience during Late Pleistocene climate swings.

Original coverage also missed the extinction link. When sapiens entered Eurasia around 45,000 years ago amid unstable MIS 3 climates, Neanderthals' higher energetic burden for rearing "enormous" infants likely lengthened inter-birth intervals and reduced population rebound capacity. Competitive exclusion becomes less about violence or superiority and more about incompatible life-history strategies. While adult Neanderthals were similar in stature to humans (if stockier), the early-life disparity reveals a developmental trade-off that ultimately proved unsustainable. This research underscores how subtle shifts in infant growth can shape species fate, reminding us that extinction often begins in the cradle.