Early humans living in Africa almost two million years ago came in a range of shapes and sizes, just as people do today, a new study claims. Researchers have found that some species were short - measuring under five feet tall - while others would have grown to heights of almost six foot. The study is the first in 20 years to compare the body size of humans who lived between 1.5 million and 2.5 million years ago. Early humans living in Africa almost two million years ago came in a range of shapes and sizes, just as people do today, a new study claims. This image shows the skeleton of the ‘Nariokotome Boy’ (Homo ergaster) Three species are generally recognised to have roamed Africa during this time frame: Homo habilis, Homo rudolfensis and Homo ergaster . Researcher Dr Jay Stock, from Cambridge University's Department of Archaeology and Anthropology, said: 'If someone asked you 'are modern humans six foot tall and 70kg?' you'd say 'well, some are, but many people aren't, and what we're starting to show is that this diversification happened really early in human evolution.' Nutrition and local environmental factors probably played a role in making some early humans larger than others. Experts also believe that sexual dimorphism (pronounced differences in appearance between males and females, such as size) might have played a part too. ‘However, almost all studied… groups include smaller and larger individuals and assessing sex based on the isolated and fragmentary postcranial remains of early Homo is nearly impossible,’ they say in the study. Another possibility, thought to be less likely, is that there were numerous species belonging to the human family Homo that varied in appearance. Measurements of fossils from sites in Kenya, Tanzania, South Africa, and Georgia in eastern Europe, revealed significant regional variation in the size of early humans during the last Ice Age. Some groups, such as those living Olduvai, Tanzania, measured just 4.8 feet on average, while those from the Koobi Fora region of Kenya grew to heights of 5.8 feet. The evidence also suggests that big bodies and long legs were not prerequisites for spreading out of Africa into Europe and Asia. The main increase in body size occurred tens of thousands of years after the small, primitive human Homo erectus migrated out of Africa. Fossils show that Homo erectus, which averaged less than five foot in height and weighed less than eight stone, was living in Georgia 1.77 million years ago. Some groups, such as those living Olduvai, Tanzania, measured just 4.8 feet on average, while those from the Koobi Fora region of Kenya grew to heights of almost six foot. A table showing the variation is pictured . Measurements of fossils from sites in Kenya, Tanzania, South Africa, and Georgia in eastern Europe, revealed significant regional variation in the size of early humans during the last Ice Age. This the landscape of the West Turkana region of Kenya is where the skeleton of Homo ergaster was found . 'The evolution of larger bodies and longer legs can no longer be assumed to be the main driving factor behind the earliest excursions of our genus to Eurasia,' said co-author Manuel Will, from Tubingen University in Germany. The scientists, whose findings are reported in the Journal of Human Evolution, developed a method of calculating the height and body mass of individuals from small fossil fragments, some no bigger than toes. Dr Stock said: 'In human evolution we see body size as one of the most important characteristics, and from examining these 'scrappier' fossils we can get a much better sense of when and where human body size diversity arose. 'Before 1.7 million years ago our ancestors were seldom over five foot tall or particularly heavy in body mass. 'When this significant size shift to much heavier, taller individuals happened, it occurred primarily in one particular place - in a region called Koobi Fora in northern Kenya around 1.7 million years ago. 'That means we can now start thinking about what regional conditions drove the emergence of this diversity, rather than seeing body size as a fixed and fundamental characteristic of a species.' ‘The results demonstrate chronological and spatial variation, but no simple temporal or . geographical trends for the evolution of body size among early Homo….suggesting that migrations into Eurasia were not contingent on larger body sizes,’ the study says . Body size has been implicated as a factor contributing to both brain evolution and the first hominin dispersals into Eurasia . One argument suggests that as lower limbs lengthened and hominins assumed limb proportions more similar to modern humans, they became more mobile and changed their foraging behaviour and diet. But fossil fragments have now shown a richer variety of sizes and this may not be the case. The ecomorphological model says that Homo ergaster was the first hominin to colonize other continents due to its energetically efficient bipedal locomotion, long distance travel abilities, large home range sizes and habitat tolerance. But fossil evidence for body size now suggests the marked increase of body size variables in early Homo took place after 1.8 Million years in eastern Africa. By this point, the dispersals already happened, suggesting that migrations into Eurasia were possible without a significant increase in body size and possibly lower limb length. Interestingly, the study says that there was an increase in body size at the start and end of the period studied, which suggests that factors other than chronology also influenced the body size of early humans.
Experts developed a method of calculating the height and body mass of individuals from small fossil fragments, some no bigger than toes . Researchers found early man ranged from 4ft 8 inches to almost 6ft . It has been said ancestors left Africa as a result of developing longer legs . But this study suggests that there may have been another driving force . Experts also claim regional conditions may be to blame for diverse shapes . This suggests body size is not a fixed characteristic of a species . It is the first study in 20 years to compare the body size of humans who lived between 1.5 million and 2.5 million years ago .