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[lalaloo73]

I'm taking an online nutrition class.  our current topic of the week is "are you a vegetarian?".  someone in the class posted a response with a really crappy attitude and incorrect information.  (read below)

"Humans are predators.  That is how our bodies are built, from the shape of our teeth to the placement of our eyes.  I for one completely

Comments

[tonights]

Well... I don't know that I would say "humans are predators," but humans are biologically opportunistic omnivores. We have teeth & a long intestine built to let us deal with meat along with plant matter, and we lack the digestive apparatuses common to ruminants and other strictly herbivorous organisms - so I'm also not sure what you mean about her information being wrong. Humans are classically omnivorous in all relevant anatomical areas. We do have the choice whether or not we want to consume animal protein, but we are certainly evolutionarily equipped to do so.

I don't think there's anything wrong with her attitude, either. She isn't forcing you to eat meat, just stating facts.

[tonights]

Oh, and your eye placement argument is incorrect. Predatory animals have binocular vision for stereopsis/increased perception/ease of chasing things down. Prey animals have eyes on either sides of their head to increase their field of vision. If what you're saying is true, humans would have eyes where their ears are.

[lalaloo73]

hmm. good point.

[shaydlip]

No, it is not incorrect.

ALL primates have forward facing eyes- and guess what, most are not meat eaters.

There's a considerable amount of debate on why stereoscopic vision evolved in the first primate groups, some thinking it's so that primates can navigate the 3D arboreal environment, so you would need it for depth perception for jumping etc. There's other people thinking that the first primate was a visual predator, a very very small animal like the tarsier who ate insects and small things like that.

So if we go with the visual predator hypothesis, then why do all primates still have stereoscopic vision? Wouldn't it then be maladaptive? Well, yes, but primates started being social so you could have more eyes for predators but keeping your stereoscopic vision.

[sollersuk]

Omnivore certainly does not equal predator; however, hunting one's own meat has advantages over hanging around for other predator's leftovers and competing with other scavengers.

And (from my Human Skeletal Remains in Archaeology course) the point at which humans were at their healthiest, biggest, most robust and most long-lived was a stage at which they were definitely hunting. Me for the Mesolithic diet as much as possible... when I can afford it!

We may not have evolved originally as hunters, but it seems to be what does best for us.

So... yes and no!

[mexicanwine]

in fact when humans switched to horticultural and then agricultural lifestyles, we incurred lots of negative side effects, and it's assumed that we stopped hunting because of "cultural" or "enviormental pressures," because when we did we suffered highly increased incidents of tooth decay, infant deaths, osteoperosis, and correct me if this isn't correct, the typical lifespan decreased, and remains were found in greater decay than generations previous. it really does not seem to make any sense that we stopped eating meat.

not to mention it's hypothesized that the average "work week" in order to obtain the amount of food to live on grew from a probable 3 or 4 days to 6 or 7, which didn't help us physically. berries and nuts provide much less nutrition and to subsist off them entirely would probobly be more work than caring for your personal garden 7 days a week.

[sollersuk]

We did indeed. Apparently it's possible to spot when agriculture started in any place simply by looking for tooth decay. And we found it very interesting to look at how many cultures had Golden Age/Garden of Eden type myths about how once everything was great but then people had to start farming.

One suggestion for the reason has been destruction of natural resources: the hills above where I live used to be forested, but it appears that in the Mesolithic they discovered that if woodland is burnt, the first thing to grow back is hazels. They overdid it, and nothing grew back; and apart from Forestry Commission fir trees (that are struggling) it's been sour peat bog ever since.

[lilyayl]

Body aside, point out that humans are thinking creatures who can choose whether or not to be defined fully by their body/limitations/etc. Even if the human body is designed for the purpose of being a meat-eating predator, that does not mean that humans must be predators and eat meat. I am a girl. My body is designed to bear children and create life. I, however, do not wish to become pregnant. That is my choice. By her definition, I should accept the fact that my body is a baby-making machine and pump out the babies. Instead, I choose to be defined not by my body, but by my own ideas and decisions.

The body and its purposes aside, being a vegetarian or not is a choice. We have the ability to decide how we wish to feed ourselves.

[timbrel]

This.

[amadruadaboleyn]

Aren't eyes on either side of the head an adaptation for predator avoidance, not forward-facing ones?

Other than that, I agree with you...although, I wouldn't start off a post (in an academic context) by saying "uhhh, no. you're wrong." That's just me, though.

[lalaloo73]

you're right. i was irritated when i wrote that. thanks.

[caerbannogbunny]

There are several schools of thought relavant to what you're talking about

[shaydlip]

First, evolutionary psychology has identified several behavioral adaptations--including much of our hand-eye coordination skills--as probably being derived from and for hunting. This may be traits maintained and modified from our insectivorous ancenstry, but we have maintained them pretty well.

Our closes insectivorous ancestor would have been about 60 mya, so probably not. Also, ususally indigenous populations hunt not by spears but by tracking and "running" down animals over long periods of time. Humans have a much better ability for longevity than quadrupedal animals.

Also, many of our gender differences unrelated to sexual selection and reproduction appear to be tied to a hunting vs. "gathering" dichotomy... I highly doubt this as well. The majority of sex differences in terms of the body are due to females needing to bear children more than anything else. It's significantly more difficult for human females to bear children than other species, except for maybe ungulates (horses

[caerbannogbunny]

"Our closes insectivorous ancestor would have been about 60 mya, so probably not. Also, ususally indigenous populations hunt not by spears but by tracking and "running" down animals over long periods of time. Humans have a much better ability for longevity than quadrupedal animals."

Right...

...but I'm talking about skills manifesting from neuromechanisms/design and not the more morphological and physiological differences from running. Humans have been tool users for a very long time and--assuming the insectivore descent is correct--tracking moving objects and making them connect in a three dimensional world for a very, very long time. That tends to be a more predatory skill than an herbivorous skill. Generally speaking, all a herbivore has to do is locae the plant--which stays still--and procure the parts it wants to eat. An argument for evading predators... making sure things do NOT connect in a three dimensional world could be had except those are more proactive skills than predictive.

"I highly doubt this as well. The

[shaydlip]

What do you consider are gender differences unrelated to sexual selection and reproduction?

...but I'm talking about skills manifesting from neuromechanisms/design and not the more morphological and physiological differences from running. Humans have been tool users for a very long time and--assuming the insectivore descent is correct--tracking moving objects and making them connect in a three dimensional world for a very, very long time. That tends to be a more predatory skill than an herbivorous skill. Generally speaking, all a herbivore has to do is locae the plant--which stays still--and procure the parts it wants to eat. An argument for evading predators... making sure things do NOT connect in a three dimensional world could be had except those are more proactive skills than predictive.

What are you considering the insectivorous ancestor? Chimpanzees?

I also do not appreciate your smirk, what could you hope to gain from it? You have lj-put me down?