The Middle Pleistocene site of Sima de los Huesos in Sierra de Atapuerca, S
pain, has yielded around 2,500 fossils from at least 33 different hominid i
ndividuals'. These have been dated at more than 200,000 years ago(2-4) and
have been classified as ancestors of Neanderthals(5,6), An almost complete
human male pelvis (labelled Pelvis 1) has been found, which we associate wi
th two fragmentary femora. Pelvis 1 is robust and very broad with avery lon
g superior pubic ramus, marked iliac flare, and a long femoral neck. This p
attern is probably the primitive condition from which modern humans departe
d. A modern human newborn would pass through the birth canal of Pelvis 1 an
d this would be even larger in a female individual. We estimate the body ma
ss of this individual at 95 kg or more. Using the cranial capacities of thr
ee specimens from Sima de los Huesos, the encephalization quotients are sub
stantially smaller than in Neanderthals and modern humans.