A Kangaroo is bipedal like us. then why has it not evolved a bigger brain as we have?

Question

Why is it nasty cuxts never allow email?

Answer 1

Apparently kangaroos have never seen the television commercial of which it slogan is;

"BEEF",

"It's whats for dinner"!

The problen is, that I can't see how any evolutionist wiil ever be capable of convincing me, or any other reasonable, rational person.

That some ooomphteen oompa loompa years ago, some monkey did see that commercial.

If that isn't rediculous enough, then they want you to believe, that the monkey who was sold on the idea of having a Rib Eye for dinner. Was one who did his fine bovine dining in Africa. Of all places.

Residents of that continent, even in their current modern form of human, encounter a next to impossible time of eating beef.

Most there can't find anything at all to eat. Much less a 32 oz. carving of Prime Rib with horseradish all over it.

I'll tell you, the things these people want you to believe?

I might have believed it. If they had manufactured the story to have said that;

"Once upon a time, there was a monkey who was so incredibly hungry to be more intelligent than any other monkey who ever existed. That he ate a whole side of beef....

In Texas!

Then it would at least be believable, even if still imfu*kingpossible!

Answer 2

They have been designed to do what they do, and they do it very well.

We have also been designed.

Evolution has nothing to do with reality!

Answer 3

Because they eat low nutrient foods, and brains take a lot of energy to run. Maybe if they were eating more fat and protein they'd be able to get smarter.

Answer 4

Because they do not have thumbs.  And also they evolved in Australia whereas Homo Sapiens evolved in Africa which has a much more diverse ecosystem.

Answer 5

Firstly, given that diet has somehow become a factor in this discussion, it's worth mentioning that carnivorous kangaroos did exist in Australian prehistory, and that none of those lineages exhibited any greater trend toward larger relative brain size than to extant species.

   The simple fact is that intelligence, central as it undoubtedly is to H. sapiens's history, is not an evolutionarily optimal solution under most conditions.  Chimpanzees are vastly more intelligent and dexterous than kangaroos, but were never a particularly successful species, even before human-induced habitat destruction.  The human mind is the product of a highly contingent series of events in evolutionary history, not the manifestation of any teleological tendency toward greater complexity.

Answer 6

Maybe because it didn't become a carnivore as well.  Protein is brain food.

Answer 7

.According to the theory of evolution animals change in order to meet the demands of their environment. If you have a situation where there are no challenges there will be no change.The marsupials  live in an area where they have no natural enemies.

Answer 8

Does my brain have something to do with my legs?

Answer 9

Well according to the book , The Truth About History, How New Evidence is Transforming The Story Of The Past, by Barnes and Noble Book stores----when humans started eating meat (protein) our brain started to develop faster.

Perhaps it is the protein in the Kangaroos diet!  Or perhaps it is just God's will.  I think it would be kind of cool to have a Kangaroo for a best friend.  Someone insults you in a bar, and your friend Kangaroo will  POW!

Thanks for the great question and inspiring a funny image!

Answer 10

The question of how humans evolved a larger brain has not been answered, and the theory of eating meat is just that - a theory (and many anthropologists believe this to be a weak theory).  There is an abundance of theories and one is that being upright could promote bigger brains (such as being upright keeps the brain cooler and thus able to grow larger).  

But the thing is that larger brains are likely due to a combination of variables, and the kangaroos just don't have that combination.

Also, for fun, we should reclassify kangaroos as tripedal because they use their tails like an extra leg.

Answer 11

Ostriches, emus, penguins are also "bipeds." Why haven't they?

Perhaps more important is the ratio of body mass to brain size. Humans have a fairly high ration compare to the critters we're discussing. However "human and mouse ratios are roughly identical" http://serendip.brynmawr.edu/bb/kinser/I...

So other factors must have an influence.

The link below discusses allometry. "The following equation was developed in the late 19th century by Snell: E=CS^r, where E is the weight of the brain, S the body weight, C is a constant "cephalization factor", and r an epirically determined exponential constant. " Once past the math there's a good chart that suggests why humans have the intelligence.