Freethought & Rationalism Archive

Marduk · 08-04-2002, 02:42 PM

I saw a show on TV the other night about Human Evolution. They say when we first came down from the trees and started to eat meat, the high fat of the meat helped to develop our big brains.
Why did this only work for primates? Cats have always eaten nothing but meat, shouldn’t they have gotten the bonus brains?

Deimos · 08-04-2002, 03:15 PM

I don't think that the consumption of meat (and the associated fat content) leads to the development of a larger brain, rather the increase in available energy makes it possible to sustain a larger brain if this prove to be advantageous.

Coragyps · 08-04-2002, 05:05 PM

I read a news blurb the other day related to this - specifically, omega-3 fatty acids from fish and organ meats (liver. brains,...) were hypothesized to make bigger brains possible, particularly during fetal development and infancy. But surely the genetic wiring that our forebears had was equally important - without the much greater expression of brain-related genes recently found in humans, we couldn't have had the internet and Billy Bass.

anakata · 08-04-2002, 05:59 PM

This is probably referring to Gibbons A. American Association of Physical Anthropologists meeting. Humans' head start: new views of brain evolution. Science 296:835. I have the full text of the paper online at <a href="http://www.anakata.hack.se/papers/pdf/Science-296-835.pdf" target="_blank">http://www.anakata.hack.se/papers/pdf/Science-296-835.pdf</a> , for those who're interested.

[ August 04, 2002: Message edited by: anakata ]</p>

One of the last sane · 08-05-2002, 06:24 PM

Aren't orangs and gorillas meant to be smart? They are vegetarians aren't they?

GeoTheo · 08-06-2002, 07:12 AM

Big brains are a valuable thing to have. They come at a high reproductive cost however. Organisms seem to evolve as large a brain as they can afford. Meat is much higher in calories than vegetable matter. By hunting and bringing meat to females bearing young hominids could afford the longer gestation and delayed childhood that comes with a big brain. Anthropologists speculate that this created kind of a positive feedback system along with other factors related to bipedalism. The more meat in the diet the more calories devoted to developing brains, the bigger the brain the better the skill at hunting and so forth.

Marduk · 08-06-2002, 03:21 PM

"Aren't orangs and gorillas meant to be smart? They are vegetarians aren't they?"

They are vegetarians but not as smart as chimps, who often hunt, kill and eat monkeys.

I saw a clip on TV of a gang of chimps tracking and catching a monkey, 2 'chasers' and 2 who stayed ahead of the monkey to grab it, pretty clever and organized.

Mageth · 08-06-2002, 03:36 PM

Orangutans are sometimes classified as frugivores (diet primarily of fruits, nuts and the tender shoots, roots, buds and leaves of plants). Others classify them as omnivores because they occasionally eat insects, bird's eggs and even meat.

From <a href="http://www.geocities.com/gunungpalung/orangutans.html" target="_blank">here:</a>
"Orangutans have been seen to eat meat only on rare occasions. In Sumatra, three adult females have been observed on seven occasions to hunt and eat slow lorises, and one female was observed to eat a gibbon. At Gunung Palung, a juvenile female orangutan once caught and ate a rat. "

lpetrich · 08-06-2002, 04:11 PM

In general, being a carnivore requires having more brains than being a herbivore; this is because of seeking prey that tries to evade its predators, rather than prey that stays in place essentially all the time.

An exception is when one lives in trees and tries to grow larger than a typical squirrel. Falling out of trees then becomes a serious hazard, and one either becomes very cautious (sloths) or gets well-developed brains for doing the tree-branch navigation (primates).

Claudia · 08-07-2002, 08:11 AM

I have read in a book (in French) written by various (french) scientiststhat it was not so much to eat meat which helped to have the energy needed to develop big brains, but to eat "good quality food" which means meat, but also energetic food (which brings more energy for less gathering work). Which has increased when our ancestors begun to live more on nuts and roots (compared to leaves and fruits), then again when use of fire made some food easiest to digest. If meat was the major explanation, chimps which eat quite a lot of animal proteins would also have bigger brains.

08-04-2002, 02:42 PM	#1
Marduk Veteran Member Join Date: Aug 2000 Location: the 10th planet Posts: 5,065	Meat eating primates I saw a show on TV the other night about Human Evolution. They say when we first came down from the trees and started to eat meat, the high fat of the meat helped to develop our big brains. Why did this only work for primates? Cats have always eaten nothing but meat, shouldn’t they have gotten the bonus brains?

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08-04-2002, 03:15 PM	#2
Deimos Junior Member Join Date: Aug 2000 Posts: 97	I don't think that the consumption of meat (and the associated fat content) leads to the development of a larger brain, rather the increase in available energy makes it possible to sustain a larger brain if this prove to be advantageous.

08-04-2002, 05:05 PM	#3
Coragyps Veteran Join Date: Aug 2001 Location: Snyder,Texas,USA Posts: 4,411	I read a news blurb the other day related to this - specifically, omega-3 fatty acids from fish and organ meats (liver. brains,...) were hypothesized to make bigger brains possible, particularly during fetal development and infancy. But surely the genetic wiring that our forebears had was equally important - without the much greater expression of brain-related genes recently found in humans, we couldn't have had the internet and Billy Bass.

08-04-2002, 05:59 PM	#4
anakata Regular Member Join Date: Jun 2002 Location: Sweden Posts: 194	This is probably referring to Gibbons A. American Association of Physical Anthropologists meeting. Humans' head start: new views of brain evolution. Science 296:835. I have the full text of the paper online at <a href="http://www.anakata.hack.se/papers/pdf/Science-296-835.pdf" target="_blank">http://www.anakata.hack.se/papers/pdf/Science-296-835.pdf</a> , for those who're interested. [ August 04, 2002: Message edited by: anakata ]</p>

08-05-2002, 06:24 PM	#5
One of the last sane Senior Member Join Date: Jun 2002 Location: hereabouts Posts: 734	Aren't orangs and gorillas meant to be smart? They are vegetarians aren't they?

08-06-2002, 07:12 AM	#6
GeoTheo Veteran Member Join Date: May 2002 Location: Bemidji Posts: 1,197	Big brains are a valuable thing to have. They come at a high reproductive cost however. Organisms seem to evolve as large a brain as they can afford. Meat is much higher in calories than vegetable matter. By hunting and bringing meat to females bearing young hominids could afford the longer gestation and delayed childhood that comes with a big brain. Anthropologists speculate that this created kind of a positive feedback system along with other factors related to bipedalism. The more meat in the diet the more calories devoted to developing brains, the bigger the brain the better the skill at hunting and so forth.

08-06-2002, 03:21 PM	#7
Marduk Veteran Member Join Date: Aug 2000 Location: the 10th planet Posts: 5,065	"Aren't orangs and gorillas meant to be smart? They are vegetarians aren't they?" They are vegetarians but not as smart as chimps, who often hunt, kill and eat monkeys. I saw a clip on TV of a gang of chimps tracking and catching a monkey, 2 'chasers' and 2 who stayed ahead of the monkey to grab it, pretty clever and organized.

08-06-2002, 03:36 PM	#8
Mageth Contributor Join Date: Jul 2001 Location: Deep in the heart of mother-lovin' Texas Posts: 29,689	Orangutans are sometimes classified as frugivores (diet primarily of fruits, nuts and the tender shoots, roots, buds and leaves of plants). Others classify them as omnivores because they occasionally eat insects, bird's eggs and even meat. From <a href="http://www.geocities.com/gunungpalung/orangutans.html" target="_blank">here:</a> "Orangutans have been seen to eat meat only on rare occasions. In Sumatra, three adult females have been observed on seven occasions to hunt and eat slow lorises, and one female was observed to eat a gibbon. At Gunung Palung, a juvenile female orangutan once caught and ate a rat. "

08-06-2002, 04:11 PM	#9
lpetrich Contributor Join Date: Jul 2000 Location: Lebanon, OR, USA Posts: 16,829	In general, being a carnivore requires having more brains than being a herbivore; this is because of seeking prey that tries to evade its predators, rather than prey that stays in place essentially all the time. An exception is when one lives in trees and tries to grow larger than a typical squirrel. Falling out of trees then becomes a serious hazard, and one either becomes very cautious (sloths) or gets well-developed brains for doing the tree-branch navigation (primates).

08-07-2002, 08:11 AM	#10
Claudia Senior Member Join Date: Apr 2001 Location: France Posts: 715	I have read in a book (in French) written by various (french) scientiststhat it was not so much to eat meat which helped to have the energy needed to develop big brains, but to eat "good quality food" which means meat, but also energetic food (which brings more energy for less gathering work). Which has increased when our ancestors begun to live more on nuts and roots (compared to leaves and fruits), then again when use of fire made some food easiest to digest. If meat was the major explanation, chimps which eat quite a lot of animal proteins would also have bigger brains.

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