In Africa (and eastern Europe before the last ice age), there are beaucoup ungulates and ruminants: antelope, gazelles, buffalos, rhinos, elephants, hippos, gnus, giraffes, zebras (and just several centuries ago in Europe: woolly rhinoceros, giant sloths, woolly mammoths, horses, asses, etc.). There is (or was) all the space and grass in the world on our prairies, and gobs of forest for the forest-dwellers, yet here is a species count, to the best of my memory: pronghorn antelope, American bison, musk ox, deer, elk, moose. Why is the new world so short on species variety in these animals? I’m not talking about head count here, but diversification. Zoology majors?
I think the question is more one of “Why did they die?” Brontotheres, titanotheres, uintatheres, etc–all incredible looking critters.
They were here at one time, but now they, and their descendants are gone.
The American megafauna die-off of about 10K years ago is
still one of the mysteries of paleontology, but I think
the experts are leaning more and more towards the notion
that human predation was the cause.
Though why human hunting didn’t spell doom for elephants, rhinos, &c., in the old world I don’t know.
What I do know is that I find it much harder to get excited
about our American fauna such as beavers, badgers, and
coyotes, than I do when it comes to elephants, giraffes,
gorillas, rhinoceroses, wild horses, chimpanzees, leopards,
I coiuld go on and on…
Then, javaman, did the new world indeed have many more species 10K years ago and before? I know that we have far less ANIMALS now, but did we have a lot more species? Since my original post, I remember that the new world had their own mammoths, and that they probably died off as a result of human predation (helped by climate change). Did we have many other species as well? [/semi-hijack – I have always found it interesting, if it is true, that horses evolved in the new world, but trekked over the then-exposed land bridge from Alaska to Siberia. They did not exist for thousands of years in the new world until European explorers brought them back a few hundred years ago! end semi-hijack/]
I’m not a zoo major or even minor for that matter but I did notice that your comparing animals indiginous to Africa to those of North America. Don’t know too much about South American animals.
Just leveling the playing field.
Jared Diamond talks about the possible impact of human hunters on American megafauna in his book “Guns, Germs and Steel.” Basically, Old World critters co-evolved with homonids and learned to be wary of those skinny, upright monkey that carry long, sharp sticks. New World critters had no such in-bred fear, and thus may have been easier prey for the proto-Indians.
As for number of species, just a WAG here, but perhaps ungulates first evolved in the Old World and then radiated out. In which case the Americas would have been on the fringe of their range, the last area colonized by the few hardies able to cross at Bering, and thus would have had fewer species.
OK, now, the critters I mentioned all significantly predate the appearance of hominids in the New World.
They (more varieties) used to be here, but they all died out–some years before the first Injuns even had the chance to make bronto burgers, uinta stakes, or titano ribs.
Besides mammoths, there were mastodons, sabertooth cats,
giant sloths, giant vultures (well, OK, maybe not “giant”–
I think they were about the size of a large condor). Those
all died out within the past 10-12k years. Other extinct
animals included the above mentioned titanotheres, but I think they’re supposed to have died out earlier.
About the “giant” vultures…maybe they were bigger than
any living bird. I’ve heard somewhere that the Native Americans have legends about giant birds, whence the name
“Thunderbird”.
Speaking of native Americans, does anyone know about myths that would demonstrate a legendary memory of mammoths? I have heard that one tribe’s myths say that their ancestors
hunted animals “as tall trees”.
There still are a lot of ungulates - moose, wapiti, bison, pronghorn antelope, musk oxen, and several species of deer still kick around North America, and different kinds of camels and a species of tapir infest the South. So it’s not like they’re all gone.
Most of South America’s megafauna, things like toxodons, got stomped when the Panamanian Isthmus developed and Northern critters began to outcompete them. The fall of North America’s megafauna I’ve heard explained as predation by humans. The typical kill involved using fire to stampede whole herds over cliffs. A little of this (well, a few thousand years) and Bullwinkle is our biggest remaining cudchewer. Follow that up with intensive agriculture and pressure from farmers, just like in almost ungulate free Europe and central China, and even bison are in trouble.
It’s the scale that’s supposed to be the key. Thousands dead from a mad charge into a canyon versus a few guys knocked off by louts waiving sticks. If I get the chance I’ll look for a site to reference.
When the Panamanian land birdge deveolped, it let ungulates into South America. Competition with the new ungulates killed off most South American marsuipials.
i just finished the “guns, germs, and steel” book mentioned earlier, and the author does in fact argue that those wacky humans are the cause. Humans had been evolving for a fair little while in Africa and southern Europe and were quite respectable hunters (not the masters of continents, but another predetor species that the typical prey species had to be wary off). And then about 50k years ago, something magical happened and modern humans showed up. we quickly went from being respectable hunters to the little terrors we are now; all of a sudden we had high tech weponry ( nice spears with sharp stone tips and such ) and probably had better group hunting strategies as well. the modern humans spread throughout africa and eurasia. it seems that same magical moment also gave us boats and humans first colonized australia ~40k years ago. the old world prey had been used to humans and the jump that made us “modern” humans apparently wasn’t enough to let us exterminate them ( and they adapted). but when humans reached australia there were mass extinctions of larger animals, presumably mostly of animals that tasted good :). samething happens when humans finally reach the americas ~13k ago. within 1000 years, both continents were filled with very hungry humans. All of a sudden animals that had evolved to keep from being eaten by sabre tooth’s and such meet up with the best hunters the planet had ever seen, and they were all eaten. the poor mammoths probably had no real predators, and then all of a sudden they were supposed to be afraid of these hairless monkeys? not all species went extinct, but most of the large ones (probably the ones that tasted best) did.
or so the book tries to explain. parts of the book are very interesting (the expansion of humans, domestication of plants and animals), but it is long and the pace is slow. many nights i only finished a few pages before it put me to sleep.
-luckie