A Neanderthal infant skeleton described in research highlighted by New Scientist has revealed that our ancient relatives may have started life significantly larger and grown far more rapidly than modern human babies. The findings, based on one of the most complete Neanderthal infant remains ever discovered, suggest that early development in these extinct hominins followed a very different biological rhythm from Homo sapiens, with implications for how they adapted to Ice Age environments and why they eventually disappeared.
The study focuses on an infant known as Amud 7, whose nearly complete skeleton was uncovered in 1992 in Amud Cave, located roughly four kilometres from the western shore of the Sea of Galilee in what is now Israel. The child lived between 51,000 and 56,000 years ago, during the late Neanderthal period in Eurasia. Researchers led by Ella Been at Ono Academic College conducted a detailed anatomical and dental analysis of the remains, combining microscopic examination of tooth development with measurements of bone growth and brain size indicators. Because of preservation limits, the infant’s sex could not be determined.
What makes Amud 7 particularly striking is the mismatch between different indicators of age. Based on tooth eruption patterns and internal dental development, the infant appears to have been around six months old at the time of death. However, when researchers examined bone length and cranial development, the skeleton more closely resembled that of a modern human infant between 12 and 14 months old. This discrepancy suggests that Neanderthal babies developed physically at a significantly faster rate than previously understood, at least in terms of skeletal and brain growth.
The researchers compared Amud 7 with two other rare Neanderthal infant remains: Dederiyeh 1 from Syria, aged around two years, and a three-year-old child discovered at Roc de Marsal in France. In all three cases, a similar pattern emerged. Skeletal development appeared advanced relative to dental age when compared with modern Homo sapiens growth trajectories. Ella Been told New Scientist that the consistency across multiple individuals indicates this is not an anomaly but a broader biological pattern in Neanderthal development.
The study suggests that Neanderthal infants experienced an unusually rapid phase of body and brain growth in early life, paired with comparatively slower dental development. This creates a developmental mismatch when viewed through the lens of modern human biology, making direct age comparisons misleading. Instead of developing along the same timeline as Homo sapiens, Neanderthal infants likely followed a distinct growth curve shaped by different evolutionary pressures.
Researchers believe this accelerated growth may have been linked to the harsh environments Neanderthals inhabited across Ice Age Eurasia. Larger bodies are more effective at conserving heat, while smaller bodies lose warmth more quickly. Faster early growth would therefore have been advantageous in cold climates, helping infants reach a more thermally stable body size sooner. However, this adaptation likely came with significant energetic costs, meaning Neanderthal mothers may have faced intense biological demands during pregnancy and breastfeeding.
Despite these early differences, the study indicates that growth patterns begin to converge later in childhood. By around seven years of age, Neanderthal and Homo sapiens children appear to follow similar developmental trajectories, particularly in terms of body size and overall growth rates. According to Been, this suggests that the most significant divergence between the species occurs in the earliest stages of life, rather than persisting into later childhood or adulthood.
Chris Stringer of the Natural History Museum in London, a leading authority on human evolution, described Amud 7 as an important missing piece in understanding Neanderthal development. He argues that the evidence supports a model in which Neanderthal growth occurred in three distinct phases: an initial stage in which dental and body development were closely aligned, followed by a rapid surge in skeletal and brain growth during infancy and toddlerhood, and finally a later stage in which dental and physical development realigned while brain growth remained comparatively rapid.
This complex developmental pattern challenges earlier assumptions that Neanderthals simply mirrored modern human growth at a different scale. Instead, it suggests a fundamentally different strategy for early life development, possibly reflecting adaptations to energy demands, environmental stress, and survival in colder climates. Adult Neanderthals, the study confirms, ultimately reached similar overall body sizes to Homo sapiens, though they tended to be shorter and more robust in build.
The findings add to a growing body of research, reported in New Scientist, that is reshaping scientific understanding of Neanderthal biology and evolution. Other recent genetic and archaeological evidence suggests that Neanderthal populations experienced significant decline during cold climatic periods around 75,000 years ago, reducing genetic diversity and potentially weakening their long-term survival prospects. When combined with the new developmental data, a picture emerges of a species highly adapted to extreme environments but potentially constrained by high biological costs in early life.
These insights also highlight the rarity and scientific value of infant Neanderthal remains. Only a handful have ever been discovered, making each one critical for reconstructing life history patterns. Amud 7, in particular, provides one of the clearest windows yet into how Neanderthals grew, developed, and adapted from infancy through adulthood.
While the study cannot determine behavioural differences between Neanderthal and modern human infants, it underscores a key evolutionary divide in physical development. Neanderthal babies were not simply smaller versions of modern humans; they appear to have followed a faster, more energetically demanding developmental pathway. In the long arc of human evolution, this difference may have shaped everything from parental investment to population resilience, and ultimately, survival itself.
