an evolutionary puzzle, new world monkeys

my daughter an archeologist tells me that there is no explanation as to how monkeys arrived in the new world...the northern land bridge with asia was responsible for most mammals traveling between old and new worlds but there no monkey fossils found in northern canada and usa, so how did they get to the americas?...best explanation so far are giant rafts of vegetation...

 

I was getting ready to argue with you but instead I looked it up.

Yep thats the best explanation. About 30-40 million years ago.

http://anthro.palomar.edu/earlyprimates/early_2.htm

 

she says that most would've starved or drowned on the voyage but over millions of years and likely tens of thousands of rafts some would have succeeded and survived...so until a fossil turns up in canada that's best they've got...

I'd never gave it any thought before until we were engaged in a discussion on when and how sapiens may have arrived in the Americas...

 

40 million years ago Africa and South America were much closer to each other, and the Atlantic between them must have been studded with small volcanic islands. So it's easy to imagine how these early monkeys must have island hopped by using rafts or driftwood. Although you won't find early monkeys in North America since it was isolated both from Africa and South America at the time, it is interesting to note that the first prosimians evolved here.

 

well there are monkeys in north america but just not as far north the usa as far as I'm aware...

the journey across the atlantic was shorter but still a significant voyage...island hopping unlikely as the mid atlantic islands wouldn't produce the large rafts of vegetation required...once on the island I imagine that's where they would stay...

 

Yes, but these are all recent arrivals who could not have migrated out of South America until the two continents approached each other 20 million years ago, or perhaps not until they connected physically with a landbridge in Panama 5 million years ago.

 

yup, that's how it looks to me as well...I would think however after five million years since the continents have been connected there should have been migration further into n america...climate shouldn't have been a factor as old world monkeys have adapted to cooler northern climates, so why isn't there fossil evidence of new world monkeys in the north?....every explanation brings still more questions...

 

An Early Human ( Pre Cro Magnon ) Braincase & upper browridge/Skull was found in South America prior to WW2.

 

I believe there was a monkey living as far as Texas once. Primates are arboreal and prefer a warmer weather, so today they're found as far north as Mexico. If you venture north of Mexico, forests are scarce. In the old world you have Japanese macaques and some other ones adapted to live in cold high altitudes in southern China. But these are still forested areas. In North America not only cooler weather, but also a lack of forest cover would work against them.

 

but some baboons are quite comfortable out of the forests like the Saudi Arabian Baboons or the Barbary Apes...so why no adaptation to ground dwelling in the Americas?...nature is good at filling niches when the opportunity arises, what predators could there be in the Americas that were more of threat than found in the old world to prevent monkey migration north?...and if they can reach Texas why not further along the gulf coast all the way to Florida or the forests of california?...and cuba had monkeys so monkeys were island hopping in the carib!...always more questions than explanations...

 

mmm, no there wasn't...unless a tourist found it in a museum...

 

I honestly don't know. The best guess I would take is that primates such as the Barbary Ape which adapted to ground dwelling would be too exposed to predators, that's why they live in isolated, hard to reach areas, here the Atlas mountains where terrain offers them an advantage. Why do they live on rock of Gibraltar but not in surrounding areas for example? In North America, plains in the past were overrun with big, speedy predators. Such predatory pressures led to evolution of elaborate defences as in Glyptodonts. In the African Savannah, baboons live mainly where there are still trees found where they can seek shelter (and where they always sleep) or on cliff sides.

 

Well interesting questions- and I love contemplating such evolutionary questions.

I would think that the desert belt in Northern Mexico, Southern U.S. is the primary reason. That is an extremely hostile environment. Could monkeys have adapted to such an environment? Clearly they could have, but I think if you look at the baboon family, much of it is adapted to living on the land, and adapting from savannah/land to desert/land would be a much easier adaptation than adapting from arboreal to desert/land.

Likewise, I am not aware of any monkeys, other than the transplanted Barbary apes, in Europe. I suspect environmental/climate factors to be involved.

Good question about Florida/Cuba- perhaps we are just seeing the result of how random such inadvertant migrations were? California is extremely unlikely, though interesting to contemplate. Monkey's would probably been able to adapt and thrive in the vast Oak forests of California.

 

Hmmm yes there was ,but it was shelved away and few Pics or Stories exist of it ( I think it was found in Argentina in late 1930's)

 

Care to find a link to some information on it?

I have not heard of anything other than modern humans ever being found in the Americas but I am open to being shown some other info.

 

yaaa and aliens built the pyramids too I read it in book and saw it in documentary so therefore it must be true ...
file that story away in the conspiracy threads forum along with the, 2nd sniper on the grassy knoll, the faked lunar landing, the carburetor 100 mpg that was hidden by the oil industry, alien abductions...

archeologists are selfish anyone that came up with a find of the century won't be "shelving" it, fame and fortune awaits any spectacular finding like that...the problem with archeologists is getting them to shut up as many tend to jump the gun proclaiming all sorts of new revelations before they have solid evidence to support their findings...

even if shelved you should have no problem finding a link to this incredible claim..

 

Most Platyrrhins are much smaller than Catarrhins, in general, and they may not have evolved in such a manner as to successfully thrive in the grasslands and deserts dominating northern central America and southern north America, especially given the number of large, predatory birds in the area and the extant rodents that can outcompete them from food supplies, to say nothing of American cheetahs, American lions, wolves, and other assorted large predators that could easily catch and devour small monkeys, whereas in Africa and Asia, baboons grow large enough to dissuade most smaller predators and solitary large ones on occasion, as well as being large enough to compete with other animals living on the savannas.

 

predators/competition in old world? predatory birds, check; rodents, check; big cats, check; wolves,check; and other assorted large predators, double check;...the predators in the Americas are no more menacing than those found in the old world...

fossil Platyrrhines found so far show they evolved to the size of ground dwelling baboons of the old world, a troop of such animals would certainly be menacing to most solitary predators...animals will grow or shrink and even reverse each process to adapt to their changing environment...

where ever there is an open niche life will evolve to fill it...nothing you've suggested explains why there is no evidence for new world monkeys not to have moved into north America in the last 5 million years...they expanded their range across the Caribbean sea as far as Cuba but couldn't get to Florida via the gulf coast?...

the old world Patas monkey a small ground dweller of open ground survives despite it's small stature...new world monkeys could have made the same adaptations...

 

What drives migration? Population pressure? New food sources? Unstable environment? Perhaps old world monkeys needed to adapt whereas the incentive for new world monkeys to migrate was not present?

 

my archeologist daughter constantly corrects me that it's technically not "migration", it's more like expansion...if there's a open niche something will fill it...there is a fish related to the piranha that is non aggressive herbivore, it was taken from s america and stocked in a geologically young river in SE asia that had very few native species as food stock...that herbivore introduced to an open niche adapted by developing a taste for human flesh and anything else that moved...

why would old world monkeys need to adapt whereas new world monkeys not?...climate change shows that much of the rain forrests in S america were grassland in the last five million years so an adaptation would've been required and larger fossil species suggest there was considerable adaptation...so why isn't there any evidence for northern adaptation???

I agree incentive does play a part, great whites sharks have little reason to adapt so they don't but at one time early on they did fill an niche that was open to be exploited...

 

Guess you can tell I'm no archeologist.
Well my thoughts are something along the lines of: Predators keep population of new world monkeys in check so population does not grow above what environment can handle; no need for expansion. Old world: not enough predators so population grew leading to expansion into more areas. All this is speculation so I will leave the hypothesis to your daughter. Does she have any ideas?

 

I have an unfinished archeology degree so I find it even more embarrassing when she needs to correct dad...it's a humbling experience to have your kids exceed you...

mmmm ya but if that were the case early man never would have left the trees let alone africa...

we had that discussion and she said as with the fish that converted to a more carnivorous diet predators also fill niches if the opportunity presents itself, so it's unlikely there is ever a shortage of predators...

she had several comments...

-if there is a niche, life will fill it...

-fossilization is a difficult process and fossils are actually quite rare, and that maybe new world monkeys did enter N America and they just haven't been discovered...

-maybe they never entered N America and there is no satisfactory explanation as to why not...


for ever question there a multitude of answers which trigger still more questions and that's why I love archeology the puzzles are awesome...

 

Primates are well adapted to their arboreal lifestyle, so you would need very strong evolutionary pressures to force them down from trees and adapt to a ground-dwelling lifestyle. In North America you did not have so much shift and fluctuations in the borderline separating forests from savannah/grasslands. For example, the prairies have been there since time immemorial. In Africa there were several cooling/drying episodes i.e. 10, 5 and 2 million years ago, when savannah gradually replaced rain forests. Hence just like human ancestors, the baboon predecessors were forced to gradually adapt to their changing environment and its new challenges.

Size probably played a role too as pointed out. Large body retains heat better. And Catarrhines overall are larger than the Platyrrhines, so they carried the necessary preadaptation to spread into the cooler, grassy environs.

 

,,,Sorry I posted the wrong thing...how to delete?

 

that same drying out of rain forests occurred in s america as well the amazon was a savannah, again the question is not answered...

and there are small old world monkeys that live on the grasslands now, so size is not a factor...and in those regions the evenings are cold due to low humidity of arid regions which questions the body heat/size suggestions...