Secrets Of Climbing June 1, 2008Posted by Mrs Weird Scientist in Animals, Environment, Evolution, Think About It.
Tags: energy, primates, treadmill, trees
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Ever had a favorite tree in your yard that you liked to climb once in a while? You probably scurried up the tree and maybe hung out for a bit before carefully making your way down to your abode on the ground. We all know that some creatures like to live up in the trees but what makes the trees such a cool place to inhabit? Scientists may have found some clues as to why early primates liked to make their home in the forest canopy. It’s all about size!
Apes and monkeys – ancestors of humans – might have ended up in the trees because of their small size. Researchers have been curious for a while now about why early primates happily lived up in the trees. Why so curious? It’s because they thought that climbing used up more energy than walking. When it comes to walking, for example, smaller animals use up more energy in comparison with larger animals. Generally, we would expect the animals to live in a way that conserves energy. So, it has been somewhat of a confusing question as to why primates would make a transition to the trees if it meant that their energy efficiency was compromised.
Using A Treadmill To Investigate
You’re probably reading the word ‘treadmill,’ and wondering to yourself what I’m talking about! Well, treadmills can be useful for many things – not just for us humans to use as exercise equipment. In this case, researchers from Duke University in North Carolina observed primates as they walked and climbed on a special treadmill that was designed for the study. The results were surprising!
The researchers found that there was no difference in how much energy was consumed for small primates whether they walked or climbed the treadmill. This means that climbing didn’t have a higher energy consumption. In this way, the small primates could make good use of the treetop environment without compromising their energy. These early primates would have been approximately the size of a very big rat. The results were published in the journal Science and the information gives us some clues about how the ancestors of these primates ended up in the trees approximately 65 million years ago.
You might be wondering what was so great about the trees? Well for early primates, moving into this new environment provided them with an abundance of tasty insects and fruits. On top of that, evolutionary changes then occurred, which means that the primates developed characteristics to help them better adapt to this new environment. For these mammals, the changes included the development of nails instead of claws. Jandy Hanna, a Duke graduate student at the time of the study, created the treadmill apparatus and measured primate activity and energy consumption. She explained:
We assumed it would be more energetically expensive for all of them to climb than to walk, so this finding was unexpected. What we have shown is that they could have made this shift into a rich environment with insects and fruits without increased energetic cost.
Ultimately, the small size of the primates meant that they could make the transition into the trees to enjoy the goodies up there. From the perspective of energy consumption, heavier animals had less incentive to climb than walk, so it was the smaller primates who had the competitive edge. Still, even if it does take more energy for humans to climb – that sure never stopped me when I was a kid and I liked climbing the tree to my playhouse.