How does upright walking work?

Explanatory page

One of the most important differences between us humans and apes is that we are able to walk permanently upright on two legs. But why is that actually so? And how does it work in the first place? What are the anatomical differences between us and our closest relatives that allow us to walk upright? On this page you will find an explanatory video in which small Emma explores the differences between an ape and a human skeleton. You will also learn why we humans "stood up" in the first place over millions of years.

Explanatory video to guess along from the BIOTOPIA Lab

Learn more!

The phenomenon of upright walking:
How humans learned to walk upright

It is pretty fascinating how our body changes over the years and hard to believe that humans were not always able to walk upright on two feet. The human remains of the ape `Udo´ were found in 2016 in the Allgäu mountain region of Bavaria, Germany.  Some scientists believe these bones show more similarities to upright walking humans than to other apes. This would provide evidence for the existence of anthropoid apes about 12 million years ago, making Udo the oldest known ape species  with these bipedal  characteristics. But how did the process of the upright walk begin?

There are a lot of theories. Natural conditions changed and the great apes had to adapt to new habitats and new challenges. Apes which had been mainly living in trees were forced to adapt to life on the plains in a new savanna environment.

The most well-known theories are:

1. Savanna-hypothesis


According to this theory, as the environment changed and our hominoid ancestors moved down from the trees and onto the plain of the Savanna, upright walking became advantageous for apes because they could look out over far distances and spot danger from far away. This better vantage point gave them more time to find safe places to hide or the chance to sneak up on their potential predators.

2. Cooler-hypothesis


This theory claims that the increased solar radiation on the apes’ body whould have caused them to stand up. In order to protect their body from overheating apes started to walk upright. Now their torso had more distance from the hot ground ground anda smaller part of their body wasexposed to the sun. The wind would also have had a greater cooling effect in this upright position.

3. Tool-hypothesis


This theory asserts that apes had to use their hands to build and use tools. Logically, having their hands free to be able to do this would be an advantage. It is debated whether better tool making was the cause or effect of upright walking.

4. Power efficiency-hypothesis


Basically this theory says that we evolved to walk upright because it allowed our early ancestors to cover farther distances as the food supply was scattered over far areas.

5. Food transportation-social-hypothesis


Similar to the Tool-Hypothesis, this theory has to do with the advantage of having hands free to collect and carry food. Having hands free while walking upright would have enabled our ape ancestors to carry food to their familly members over large distances. However, this hypothesis is also debated because it could likely be an advantageous effect, rather than the cause, of upright walking.

All these are current theories based on available evidence. As more archaeological and environmental evidence is found, new theories may emerge. We know for fact that upright walking has led to considerable anatomical differences between humans and other apes. In the video, we briefly looked together at some of the key physical differences and why they are an advantage or disadvantage to walking upright.


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