Link #4: Human Existence Can Be Traced to the Need to Smell Better

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Chain of Facts - A Connection of Facts

Link #4: Human Existence Can Be Traced to the Need to Smell Better

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We may have embraced civilization and technology, but we’re still beings who rely heavily on our instincts when it comes to making decisions in life. For instance, from our last post, you already know that there is a distinct difference between men’s and women’s ability to smell, and a difference in the severity of their body odors. However, did you know that the way we are right now can actually be traced back to our ancestors’ need to smell better?


Brains of Mammals Are Larger than Those of Other Animals

Human Brain X-Ray

Let’s understand one of the basics of the animal kingdom. It’s a well-established fact that the brains of mammals tend to be larger than the brains of other types of animals, in relation to body size.

This doesn’t mean that mammals have the biggest brains on the planet. It just means that the proportion of a mammal’s brain size to its body size is much bigger than the proportion of brain size to the body size of other types of animals. This proportion is considered to be indicative of superiority, so it’s quite important to have a big head.


Larger Brains Evolved to Get Heightened Sense of Smell

Water shrew, Neomys fodiens

In prehistoric times, when dinosaurs ruled on the planet by sheer force and size, it was difficult for any other type of animal to flourish. However, evolution found a way, by creating the first mammals, with a strong ability to detect scents and odors.

With a sense of smell that dwarfed every other type of animal, the small critter-like mammals could find their prey and run away from their predators. While the newly evolved brain was large in scale from every perspective, a double-lobed part of the brain responsible for processing smell-related information (the olfactory bulb) was particularly huge.


Human Brains Morphed Further When Survival Was Assured

Stoneage hunters

The presence of the huge olfactory bulb allowed the small mammal (which looked a lot like a shrew) to survive the adverse conditions around it. This gave evolution time to branch off other variants and versions. Hence, the class of mammals could survive. This enhanced sense of smell still exists in some mammals. Prime examples are dogs and bats.

This branching off of new variants continued and, after a significant amount of time had passed, early humans started making an appearance. Earlier versions of humans retained the large brain size but didn’t have the huge olfactory bulb. For early humans, evolution had chosen to replace the enhanced sense of smell with better vision and eyesight.

This superior vision was a better option over the sense of smell because the human species was moving toward walking upright. Superior eyesight is better than a sense of smell if you’re going to be standing up. In effect, you can say that our existence is a result of the first mammals’ need to have a good sense of smell.




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Sources:

http://www.washingtonpost.com/national/mammals-win-by-a-nose-sense-of-smell-drove-evolution-of-big-brains/2011/05/19/AFIh1H7G_story.html
http://www.bbc.co.uk/nature/13448202
http://www.jsg.utexas.edu/news/2011/05/mammals-first-evolved-big-brains-for-better-sense-of-smell/
http://www.sciencedaily.com/releases/2011/12/111214101818.htm

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