Sincere question: why did elephants do OK in Africa and Asia as opposed to the Americas. We’re not there humans there also to predate upon them? Were there other species present as easier sources for food? Less dense human populations?
Thanks for asking this important question. It is a big, controversial area, and I'll give my take on it. The basic idea is that the human line had been preying on the elephant family in Africa and Eurasia for at least 1.5 million years:
and those elephant-family members evolved defensive reactions to humans, which was partly being very aggressive toward any humans that they saw, which can be seen in African bush elephants today.
Paul Martin proposed the "Blitzkrieg hypothesis," which stated that when humans arrived in places such as the Americas, those elephant-family members had never seen two-legged predators like humans before, so they had no fear of them. Elephants did not fear much anyway, especially adults, as nothing could really prey on them. But juveniles were another matter, and the fossil evidence indicates that saber-toothed cats specialized in hunting juvenile mammoths in North America, for instance. Elephants did their best to protect their young, but there was always attrition from predators.
When humans arrived in the Americas, for instance, they were already the most successful predators in Earth's history. Nothing could stand up to them. While there is plenty of evidence that they hunted adult elephants, it would have been far easier to hunt the young elephants, and that is what may have happened. The adults may have never figured out how to protect their young from humans before they went extinct. Elephants reproduce very slowly, so targeting their young could have swiftly driven them to extinction. That is one possibility, which I think was likely.
But far more than elephants went extinct in the Americas, in only a few thousand years. Horses and camels evolved in North America over 40 million years ago, and they went totally extinct in North America when the elephants did, as well as many other megafauna species. The saber-toothed cats went extinct when the elephants did, as they no longer had prey to eat. Another aspect of that is that elephants are great terraformers. In Africa today, their habits keep the forests from invading the grasslands, so they are called a keystone species. When elephants went extinct in the Americas, it is likely that many other savanna species went extinct because the elephants no longer maintained the savanna. The mammoth steppe near the ice sheets was also likely maintained by the mammoths, and it looked a lot different from today's tundra.
This area has been a huge political football for many years, but I think that it is a no-brainer that the introduction of the greatest predator in Earth's history to "virgin" lands such as Australia and the Americas spelled the quick doom of the easy meat. They did not have time to adapt before they were driven to extinction. The adaptations of the elephants in Africa and Asia likely happened over hundreds of thousands of years. The elephants of the Americas went completely extinct in only a few thousand years, and my guess is that any elephants who saw people did not live long after that. I doubt that there was much co-existence, but even if there was, targeting the young elephants would have quickly driven the elephants to extinction. There really is no other contender in the Americas but humans, and I strongly doubt the introduced-disease hypothesis, and the climate-change hypothesis is ludicrous. Elephant-family members have always been opportunistic feeders, and they all went extinct after the ice sheets melted and it was good times again.
And it was not just the Americas and Australia that suffered the rise of behaviorally modern humans. Africa and Eurasia also lost many megafauna species with the rise of behaviorally modern humans, and all other human species went extinct. During the rise of behaviorally modern humans, Africa "only" lost 18% of its megafauna species, Eurasia 36%, North America 72%, South America 83%, and Australia lost 88%. As I wrote in my recent essay, kangaroos were too fleet-footed, and they could carry their vulnerable offspring with them, to be driven to extinction:
Sincere question: why did elephants do OK in Africa and Asia as opposed to the Americas. We’re not there humans there also to predate upon them? Were there other species present as easier sources for food? Less dense human populations?
Thanks for asking this important question. It is a big, controversial area, and I'll give my take on it. The basic idea is that the human line had been preying on the elephant family in Africa and Eurasia for at least 1.5 million years:
https://ahealedplanet.net/preview.htm#elephants
and those elephant-family members evolved defensive reactions to humans, which was partly being very aggressive toward any humans that they saw, which can be seen in African bush elephants today.
Paul Martin proposed the "Blitzkrieg hypothesis," which stated that when humans arrived in places such as the Americas, those elephant-family members had never seen two-legged predators like humans before, so they had no fear of them. Elephants did not fear much anyway, especially adults, as nothing could really prey on them. But juveniles were another matter, and the fossil evidence indicates that saber-toothed cats specialized in hunting juvenile mammoths in North America, for instance. Elephants did their best to protect their young, but there was always attrition from predators.
When humans arrived in the Americas, for instance, they were already the most successful predators in Earth's history. Nothing could stand up to them. While there is plenty of evidence that they hunted adult elephants, it would have been far easier to hunt the young elephants, and that is what may have happened. The adults may have never figured out how to protect their young from humans before they went extinct. Elephants reproduce very slowly, so targeting their young could have swiftly driven them to extinction. That is one possibility, which I think was likely.
But far more than elephants went extinct in the Americas, in only a few thousand years. Horses and camels evolved in North America over 40 million years ago, and they went totally extinct in North America when the elephants did, as well as many other megafauna species. The saber-toothed cats went extinct when the elephants did, as they no longer had prey to eat. Another aspect of that is that elephants are great terraformers. In Africa today, their habits keep the forests from invading the grasslands, so they are called a keystone species. When elephants went extinct in the Americas, it is likely that many other savanna species went extinct because the elephants no longer maintained the savanna. The mammoth steppe near the ice sheets was also likely maintained by the mammoths, and it looked a lot different from today's tundra.
This area has been a huge political football for many years, but I think that it is a no-brainer that the introduction of the greatest predator in Earth's history to "virgin" lands such as Australia and the Americas spelled the quick doom of the easy meat. They did not have time to adapt before they were driven to extinction. The adaptations of the elephants in Africa and Asia likely happened over hundreds of thousands of years. The elephants of the Americas went completely extinct in only a few thousand years, and my guess is that any elephants who saw people did not live long after that. I doubt that there was much co-existence, but even if there was, targeting the young elephants would have quickly driven the elephants to extinction. There really is no other contender in the Americas but humans, and I strongly doubt the introduced-disease hypothesis, and the climate-change hypothesis is ludicrous. Elephant-family members have always been opportunistic feeders, and they all went extinct after the ice sheets melted and it was good times again.
And it was not just the Americas and Australia that suffered the rise of behaviorally modern humans. Africa and Eurasia also lost many megafauna species with the rise of behaviorally modern humans, and all other human species went extinct. During the rise of behaviorally modern humans, Africa "only" lost 18% of its megafauna species, Eurasia 36%, North America 72%, South America 83%, and Australia lost 88%. As I wrote in my recent essay, kangaroos were too fleet-footed, and they could carry their vulnerable offspring with them, to be driven to extinction:
https://ahealedplanet.net/preview.htm#kangaroo
The surviving megafauna generally had some kind of special circumstance that saved them.
Does that answer it? Happy to discuss further.
Yes, thanks for the detailed response.