Universities running after the naked ape

16 May 2011

Scientists from LJMU and the University of Glasgow have revisited mathematical research models to investigate the controversial theory that endurance running was important in human evolution. They have discovered key findings suggesting that endurance running may have been possible for early humans around one million years ago (such as Homo erectus), but is unlikely for any earlier ancestors.

This area of research was initiated by Professor Peter Wheeler, now Dean of Science at LJMU through the mid 1980s to the early 90s, with the publication of a series of highly influential papers in The Journal of Human Evolution, which used mathematics to test ideas about the reasons why humans evolved to stand upright and lose most of their body hair – becoming ‘naked apes’ in Desmond Morris’ memorable phrase. Professor Wheeler argued that these were adaptations to help keep early humans cool on a hot African savanna.

Now Professor Graeme Ruxton (University of Glasgow) and Dr David Wilkinson (LJMU) have published a paper also in The Journal of Human Evolution, which has developed these mathematical models to allow the early humans to run around, whereas this maintained more typical lower activity levels in Wheeler’s earlier work.
Several scientists have argued that much of human body shape is an adaptation to allow us to run for long distances in hot conditions – so catching animals by running them into the ground through heat exhaustion. If so, endurance sporting events - such as the modern marathon - are hangovers from our hunting past. As all runners know, it’s an activity that generates lots of body heat, so in understanding the potential importance of past endurance hunting tactics it was important to develop computer models that allowed this aspect to be considered – alongside heating from the African sun.

The new study suggests that for endurance running to be possible an early human would need running efficiency, sweating rates and areas of hairless skin similar to modern humans. Thus the earliest upright humans may well have walked from place to place, they may even have been able to run short distances (perhaps to a tree to escape predators) but this works suggest that they could not run long distances for their supper. They also showed just how important sweating rates are (and humans are unusually sweaty mammals) in allowing long distance running in the tropics. As Wilkinson pointed out: “We are really the naked, sweaty ape!”

Ruxton adds, “In order to improve our model, it would be good to understand how water loss from prolonged sweating impairs our ability to keep running, but such data are hard to find because athletes are careful to re-hydrate regularly. Persistence hunters might have been quite dehydrated at the end of a long chase, and may have slated their thirst on the blood of the animal as soon as they caught it.”

Read about the research in the Financial Times: 

http://www.ft.com/cms/s/2/9dd60826-75f1-11e0-82c6-00144feabdc0.html#axzz1Lez3r61A

Additional background notes: The human lineage split from that of the chimpanzees some 5-7 million years ago, the fossil record suggests that our first bipedal ancestors may have occurred as early as 4 million years ago, but fossil bones can tell us little about when we first started to lose our hair.

The Journal of Human Evolution paper can be viewed at: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WJS-52KWKCN-1&_user=777686&_coverDate=04%2F12%2F2011&_rdoc=6&_fmt=high&_orig=browse&_origin=browse&_zone=rslt_list_item&_srch=doc-info(%23toc%236886%239999%23999999999%2399999%23FLA%23display%23Articles)&_cdi=6886&_sort=d&_docanchor=&_ct=30&_acct=C000043031&_version=1&_urlVersion=0&_userid=777686&md5=86866cdfe83f77111fd45196f11af866&searchtype=a