Carry on walking!

Mar 31, 2007

The next time you are struggling to carry your bags home from the supermarket just remember that this could, in fact, be the reason you are able to walk upright on two legs at all! How we have evolved to walk on two legs remains a fundamental but, as yet, unresolved question for scientists. A popular explanation is that it is our ability to carry objects, particularly children, which forced early hominins onto two legs.

Dr Johanna Watson (University of Manchester) will present work supporting this theory on Saturday 31st March 2007 at the Society for Experimental Biology's Annual Meeting in Glasgow.

Researchers looked at the energy expended when walking whilst carrying a 10kg load. Importantly, the distribution of the weight varied in each instance. Female participants, of child bearing age (20-30 years old) were assessed walking at a constant speed carrying either a symmetric load, in the form of a weighted vest or a 5kg dumbbell in each hand, or carrying an asymmetric load, which was a single 10kg weight carried in one hand, or a mannequin infant on one hip.

Results indicated that when carrying an evenly spread load humans are actually more efficient at carrying than most mammals but carrying awkward loads, such as an infant on one side of the body, uses much more energy. However this sort of carrying would have been inevitable once early hominins lost the ability to cling on with their feet. “The high energetic cost of carrying an asymmetric load, suggests that infant carrying would need to generate significant benefits elsewhere in order to be selected for,” says Dr Watson.

This work is part of a larger project, run by Dr Bill Sellers at the University of Manchester, which also uses computer simulations to try to understand evolutionary processes, particularly the way in which we and other animals move.

Future plans are to extend this study to assess the energy cost of carrying in great apes which will be very tricky indeed. Computer models of early hominins carrying will also be built to try and evaluate whether their body shape and posture - long arms and short legs - would have made them noticeably better or worse at carrying than ourselves. This will help to build up a picture of how we evolved to walk to two legs.

Source: Society for Experimental Biology

Explore further: To mark territory or not to mark territory: Breaking the pheromone code

add to favorites email to friend print save as pdf

Related Stories

Cloaked DNA nanodevices survive pilot mission

22 hours ago

It's a familiar trope in science fiction: In enemy territory, activate your cloaking device. And real-world viruses use similar tactics to make themselves invisible to the immune system. Now scientists at ...

Proposed Mars 'Icebreaker' mission detailed

Apr 18, 2014

Scientists supported by the Astrobiology Technology for Exploring Planets (ASTEP) and Astrobiology Instrument Development Programs (ASTID) have outlined the proposed 'Icebreaker' mission to Mars in a recent ...

Recommended for you

Engineered E. coli produces high levels of D-ribose

16 minutes ago

D-ribose is a commercially important sugar used as a sweetener, a nutritional supplement, and as a starting compound for synthesizing riboflavin and several antiviral drugs. Genetic engineering of Escherichia co ...

Cell resiliency surprises scientists

1 hour ago

New research shows that cells are more resilient in taking care of their DNA than scientists originally thought. Even when missing critical components, cells can adapt and make copies of their DNA in an alternative ...

User comments : 0

More news stories

Cell resiliency surprises scientists

New research shows that cells are more resilient in taking care of their DNA than scientists originally thought. Even when missing critical components, cells can adapt and make copies of their DNA in an alternative ...

Team reprograms blood cells into blood stem cells in mice

Researchers at Boston Children's Hospital have reprogrammed mature blood cells from mice into blood-forming hematopoietic stem cells (HSCs), using a cocktail of eight genetic switches called transcription factors. The reprogrammed ...