Humans and giant pandas don’t look much alike, but in one key
If you want to understand how humans evolved,
You surely wouldn’t bother studying a panda. Sure, they are cute, but they have nothing to do with us. They aren’t a close relative, and they aren’t packing a lot of brainpower.
That’s all true, but according to a new analysis, pandas might be extremely relevant to our evolution. They could help explain one of the most peculiar things about the human body: our upright posture.
Humans and pandas are both mammals, and the majority of mammals spend most of their time on four legs. From dogs and rats to bears and elephants, that’s the norm. Walking around on four legs means that your back is horizontal, parallel to the ground.
Humans are different. We hold our backs and spines vertically, at
They wanted something that wasn’t an ape or a
That’s where giant pandas come in.
In common with other bears, they spend a lot of time sitting on their bottoms, back upright. Russo and Williams wanted to find out if pandas’ spines had also changed shape in a similar way to ours. If they had, it would suggest that pandas and humans evolved their upright postures for similar reasons. On the other hand, if pandas’ spines were not like ours, that would suggest that they evolved their upright posture for different reasons.
They compared the shapes of individual backbones – vertebrae – from pandas and closely-related bears.
Compared to their closest relatives, pandas had fewer vertebrae in their lower backs, and the vertebrae were a different shape. The same change happened when our monkey-like ancestors evolved into apes.
If pandas and apes evolved their upright posture for the same reason, what could that reason be?
Traditionally, apes’ spinal shapes have been explained by their habit of swinging below tree branches using their
The same might apply to giant pandas, which famously have to spend most of their time sitting around eating bamboo. Russo and Williams think that apes probably began evolving upright postures 15-20 million years ago.
“There are fossil apes likePierolapithecus that show adaptations in their lower backs to upright posture,” they say.
The line that would lead to humans then split from the rest of the apes sometime between 13 and 7 million years ago.
Read more on BBC Earth.
Author: M. Marshall
Source: BBC Earth
Date: 20th September 2015