The relatively unknown megafauna tragedy and its relevance today
barefootmuse.wordpress.com
barefootmuse.wordpress.com
A major theme of the book is how many of the fruits we see today (especially avocados, osange oranges, honey locust pods, possibly mangoes and many other large fruits) originally evolved to be eaten by megafauna. The idea is they would eat the fruit whole and swallow the pit, and poop it out somewhere. Evidence for this is that many of the trees have defenses against non-megafauna eating the fruits, or others have out-of-proportion defenses against any living animal today, the fact that many pits will only grow if they have been scoured (for example by the digestive system of an animal), and that the pits often seem over-defended, and the fact that many of these fruits are not eaten by any living animals and often fall from the tree and rot in place.
Do people upvote articles without reading them?
Most of the interior US, especially the west, wasn't accessible until the rail roads came. It was my understanding most of the mass buffalo hunting was because of the railroads.
This is not a meaningful number either if the drop (or, more to the point, the overhunting) only really started 70 years before the end of the period.
I haven't found any clear statement about this, but the following article talks about the "19th century hunts".
The point being that Columbus is not the relevant marker, even though the article brought him up. In this sense the GP comment has a point, that's bad writing.
It is interesting that the bison continued to thrive (until the 1800s), and I guess I never thought about why they outlasted the Ice Age/predation thing that killed off the other large animals.
If I remember right, the last time I read this story was at the elephant exhibit at the San Diego Zoo, or perhaps the standing exhibit at the La Brea Tar Pits. I'm just an interested outsider, so that's good enough for me.
IIRC, the whole Bering Straits story is itself more complex than I learned in grade school. It was open longer, and was wider and bigger than originally thought. I believe humans came across in several waves that are genetically or archeologically separable. I read a lot of stuff in Science, and remember about 20%, and 50% of those memories are part-wrong, so take this with a grain of salt. ;-)
Or they just say that humans arrived here by unknown means, anyway we have 40.000 year old settlement sites, 40.000 years is time enough to extinguish whatever you want even if your population is in the hundreds...
I can imagine exotic and big game has been the prime target of humans for a very long time.
I am inclined to give the benefit if the doubt in the whole " The only place megafauna has survived to some extent to the present day is in Africa where people traditionally have lived in harmony with nature". In many hands that would be hippy happy pseudo racist claptrap. And it might be but the next paragraph points to the more realistic "harmony with nature = avoiding humans"
I have severe doubts about the overkill theory - the fossil record is fairly sketchy and so many species died out within a few hundred thousand years of us arriving on the scene that exact timings are hard to believe. On top of which the practicality seems a bit hard - I can accept that some creatures might be defenceless against men and spears (giant sloths seem likely to lose out) but I am going to struggle seeing sabre tooth tigers as easy prey for man.
Climate change, Eco system collapse and diseases carried by apes and their dogs seem to hold the occam razor prize for most likely explanations. A spear through the kidneys would just be making a bad day at the office worse for megafauna.
Bullshit.
From what I understand it's attributable to megafauna evolving alongside humans as they emerged in Africa. They had time to "learn" how to survive in the face of this new predator. In places like North America humans slaughtered and multiplied faster than their prey could adapt.
It's kind of the idea that the most successful parasites can't kill their hosts too efficiently or quickly, because then they run out of places to live. If you screw up your environment like that, it'll come back to haunt you.
You may not be surprised to hear that that was my original, much desired goal, but after much thought and experiment I realized that the abrupt discontinuity caused by the exhaustion of the nonrenewables is real, for the reason that, in practice, the rate of nonrenewable use increase as their exhaustion approaches, creating an abrupt knee that resists conversion to a closed form.
> At least, this should remove the sudden discontinuity in the slope of the nonrenewable resources function.
But that abrupt end to nonrenewables is real -- it reflects the fact that the growing colony becomes increasingly reliant on them as their exhaustion approaches. So the knee can't be removed without changing the meaning of the equation.
Oh, well -- as it turns out, there are many very common differential equations that resist conversion to closed form. Orbital systems with more than two bodies are a classic example. Another one is the integral to the common exponential function that gives us the normal distribution -- very commonly used in statistics and elsewhere, but no closed form. All applications of the normal distribution use a numerical algorithm called the "error function" to produce results -- all of them approximate, and having the drawback that they cannot be symbolically differentiated or integrated.
Maybe a much more skilled mathematician that I am could find a way around this obstacle, but I doubt it.
Nature will always be fine, whether humanity as we know it survives is the problem.
The lower population density in Africa wasn't some kind of harmony, it was a result of awful disease.
Now that many diseases are under control, Africa's population is exploding in a region where birth control was never relevant before. It is already overpopulated and still has birthrates that more than double population with each generation. Soon it will be the most overpopulated region in the world. The megafauna will require heroic efforts to save.