Friday, August 07, 2009

Weak-Jawed Humans

Harvard Professor Richard Wrangham, in his book Catching Fire, explains how the shift from raw to cooked food was the key factor in human evolution, and that this shift is evident in our anatomy - we have smaller mouths, weaker jaws, and smaller teeth.

Wrangham says:
"Our small, weak jaw muscles are not adapted for chewing tough raw food, but they work well for soft, cooked food.

In nonhuman apes these muscles often reach all the way from the jaw to the top of the skull where they sometimes attach to a ridge of bone called the sagittal crest, whose only function is to accommodate the jaw muscles. In humans, by contrast, our jaw muscles normally reach barely halfway up the side of our heads.

If you clench and unclench your teeth and feel the side of your head, you have a good chance of being able to prove to yourself that you are not a gorilla: your temporalis muscle likely stops near the top of your ear."
Here you can see the anatomical difference in jaws and teeth between us and ancient members of our Family. (The author of this video states, "This is not meant to be an accurate representation of our own lineage."):


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5 comments:

Perovskia said...

I am not a gorilla :)

Anonymous said...

I am not an animal.

Joseph Merrick

Bix said...

Joseph Merrick. I thought that name was familiar.

Bryan - oz4caster said...

That makes a lot of sense and would argue against eating a lot of tough, difficult to chew raw foods. By the same token, our digestive system has evolved from our predecessors as well and favors a more omnivorous diet compared our largely vegetarian monkey and ape ancestors.

Bix said...

"our digestive system has evolved from our predecessors as well and favors a more omnivorous diet"

I couldn't agree more.