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Comment by AbrahamParangi | Hacker News Reader

I wonder why the default assumption in archaeology of pleistocene megafauna so often is "it is unlikely that they were hunted into extinction". It seems to me that ecological pressure from Humans is the parsimonious explanation.

Two recent examples: the last major landmasses to be settled by humans were Madagascar and New Zealand. These islands were home to very unique megafauna such as Haast's Eagle, the Elephant Bird, the Moa, Giant Tortoises, a species of Hippo, Crocodiles, Lemurs larger than a human, and others.

All went extinct within several hundred years of human arrival.

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> It seems to me that ecological pressure from Humans is the parsimonious explanation.

Humans are very crafty at using the whole animal so the processing of a carcass tends to leave traces all over a settlement wherever bits get used (bone tools and whatnot).

Hunting big and necessarily rare game has a worse risk/reward tradeoff and is less efficient than optimizing for shaking an antelope/deer/elk on the regular.

The environment was being turned upside down in all sorts of places at the end of the last ice age. Humans in many cases where the did hunt things only accelerated the inevitable by a few thousand years which sounds like a lot but is the blink of an eye in terms of evolution.

Basically unless humans left evidence indicating they habitually hunted these animals it's a pretty fair bet they did so only in an occasional opportunistic manner.

"But the cave art" you say?

Nobody posts the 100th medium sized whitetail doe they got that year on social. But if me and the boys get capitalize on a once or twice in a career opportunity to bag a rhino you can bet that mofo is going on the 'gram. Simply put, rare and exceptional events get proportionately more documentation effort put into them. If you "read the docs" that any civilization has left important people and exceptional events dominate when in reality the bulk of the labor was spent on food shelter and clothing.

>The last major landmasses to be settled by humans were Madagascar and New Zealand...

Comparing the ecological impact of the relatively population dense cultures that settled these islands to the ecological impact of nomadic neolithic people (who would have hunted steppe mammals) is like comparing a skid steer to a mining shovel. Furthermore, islands tend to exacerbate the impact because they're a relatively closed system compared to the mainland where if you can't find enough to hunt and gather you pack up and move.

The quaternary extinctions start to occur in Australia around ~60k years ago, South America ~15k years ago, Madagascar ~1k years ago, and New Zealand ~700 years ago.

These numbers are very shortly after when humans first show up in each place.

While climate change probably bears some of the blame, massive climate change is actually a regular feature of the last 2.5 million years. As the earth passes through glacial and interglacial phases, the temperature varies by as much as 10°C.

The biggest change in the past cycle is us, humans, who now constitute some 36% of mammal biomass.

I suggest that extrapolating backwards from the present state, as well as from recent first-colonization events, we should assume that ecological pressure from humans -including predation, displacement, and disruption of habitat and food webs- is the principle factor.

I don’t think that people back then had the same narrative needs as we do.

One could just as well speculate that what they recorded were things important to them.

If wheat or papyrus or irrigation or agriculture were important to them, they might record those things.

But also might record great threats to survival like pests or floods or drought.

You’re take would discount people in far northern latitudes hunting whales because there are easier prey.

> Humans are very crafty at using the whole animal so the processing of a carcass tends to leave traces all over a settlement wherever bits get used (bone tools and whatnot).

Yeah, about that...

> Ice Age hunter-gatherers, foraging the bone-chilling, unforgiving steppes of what today is Russia, somehow completed a remarkable construction project: a 40-foot-wide, circular structure made from the skulls, skeletons and tusks of more than 60 woolly mammoths.

> Archaeologists have unearthed about 70 mammoth-bone structures across Eastern Europe. But this one is the oldest on the Russian plain thought to be made by modern humans. Most of the previously identified structures were small, leading researchers to conclude they were most likely used as winter dwellings on a nearly treeless landscape.

https://www.nytimes.com/2020/03/17/science/mammoth-bones-cir...

The default position is, like it should be for any scientific field, to assume nothing. Unless there is enough evidence pointing to a specific cause, the consensus will be "we don't know for sure, but here a few possibilities".

Certainly there is evidence of hunting, but was it enough to lead to extinction by itself? Knowing that there was also a shift in the climate at the same time.

It was the same story with the Cretaceous extinction, where multiple factors were put forward (See: Fantasia for example). That is, until the KT boundary was discovered, showing a clear link to the extinction and a major asteroid/comet impact.

Hopefully as more evidence comes in we'll get a better picture.

It pretty much is the default assumption, but like most complex phenomena it tends to be multifactorial. I'd recommend the quaternary extinction page on wiki for a broad sketch of general arguments. They basically revolve around the timings (which in many cases pre- or post-date human arrival) and differential impact.

[1] https://en.wikipedia.org/wiki/Quaternary_extinction

What I've read is that the evidence from encampments indicate that humans tended to hunt smaller animals and foraged for food even when larger animals were in the area. This was specifically in the context of the Clovis people hunting mammoths, but as a complete non-expert I feel I am within my rights to grossly overgeneralize.

During this period there was a much lower population of humans.

All it takes is some tribal chief to say "the person with the most rhino horns on their armour is the strongest", and suddenly even a small group of practiced hunters can quickly kill all the rhino...

But at that time humans were on foot and probably didn't range that far in general.

I have walked 30km in 8 hours and it wasn't even that hard. A tough as nails hunter gatherer who has been walking and hunting and sleeping rough his entire life could probably cover hundreds of kilometers in a hunting trip.

Sure, and you spent how much of that time looking out for predators, unfamiliar terrain, only on animal trails, other non-friendly groups of people etc?

We all know humans can run all day long, but the point is that it wasn't as easy then, and if it wasn't necessary then they probably wouldn't have taken the risk.

Bipedal movement is highly efficient. Over a multi-day period humans on foot are close to the fastest land animal when we want to be (dogs are slightly better/worse depending on the breed).

There are estimates that the population of humans in the entire world dropped as low as 10,000 - 75,000 humans[1].

In general, subsistence level tribes are just surviving, nor hunting excess animals.

[1] https://en.wikipedia.org/wiki/Toba_catastrophe_theory

> In general, subsistence level tribes are just surviving

That’s the definition of “subsistence-level”, yes.

That wiki article has a lot of counter evidence to that theory. Also, a generic bottleneck doesn’t mean the population before or after it was very low for very long. At even 1% growth rate per year 50k humans become 1 billion humans in 1,000 years. Suggesting any event based bottleneck lasts less than 1,000 years.

Not that likely without modern weapons. Hunting big animals was because of that a collective endeavor that involved most of the tribe for a long stretch of time. Hunting is time and energy extensive, not to forget the danger. Before meat preservation techniques AFAIK developed around 5000 BCE, there wouldn't be a logic for this kind of tradition to develop, as it would surely reduce survival fitness for the tribe that adopted it.

Exactly. Neolithic people had pretty bad food security. To intentionally reduce overall efficiency of the system would be folly and everyone would know it.

After the third time you dump a rhino into the tribe's food processing pipeline and waste half of it before it can be eaten there will be a new directive or there will be a new chief.

Knowing you have lots of people with the skill to kill a rhino could be good for food security. When other food sources are scarce, you can go use those rhino killing skills to feed yourselves, while other tribes who don't have experience fail to catch a rhino.

This assumes that learning and practicing a skill is easier when food is abundant, and that skill can then be used in harder times.

Armies do the same when they spend all day long practicing without actually going to war. By your argument that would be a waste of resources, but history shows that well trained armies win wars.

Don't get me wrong, if they're looking for antelope and see a rhino they'll be all over the rhino. But they're not gonna waste good opportunities to get the food they need in order to go looking for a rhino. Just like everything else in life it's a bajillion variable tradeoff with potential second and 3rd order effects. I think it suffices to say that the guy in charge of the hunting party isn't gonna risk his team getting hurt going after a rhino unless there's a damn good reason to make that gamble.

If the weather is cold (as it was) the meat will freeze and/or can be dried quickly and be preserved over the course of the winter.

Modern subsistence hunters still do this. Hunt a large animal or two at the start of winter and the meat can be frozen and then cooked all through the winter. A couple of Moose for example in modern times could provide 1000lbs of stored frozen meat for a family to get through the winter.

I am not necessarily saying that this would make it make sense for a tribe to bring down a dangerous 7000lb rhino and try to preserve it that way, but if the weather was cold during this period in Siberia it would have been possible.

But the evidence we have available to us is that even a small founding population introduced to a new ecosystem will result in the fairly rapid extinction of megafauna.

I used to dismiss people who claimed that it was due to political correctness, and the unwillingness of media to attribute anything negative to native populations.

...now I'm not so sure.

It could be that climate change precipitated both human technological evolution, which in turn led to the massive expansion of the human range, and the mass-extinction of mega fauna.

Climate being responsible for both would explain why the extinction was global in scale and coinciding with the spread of humans.

This is not to say that your theory is wrong. Just that this is a potential alternate explanation.

Another thing that I observe is the insane amount of land animals that look beautiful.

Compared to sea animals where, I would say, a majority looks quite disgusting or they have some features that are not appealing to the human eye.

Humans have not only forced some animals to extinction but they have probably killed animals that they found less appealing.

Many predators look cool too. I find it unlikely that we killed all of ugly lions and wolves just because you know, fashion.

My blind guess is fur. We mostly like fur and there is no fur in water.

Sea otters were hunted nearly to extinction for their fur.

The exception that proves the rule?

I never understood this expression until now.

Outside of its context of referring to exceptions in legal and other human-made systems of rules evidencing the existence of a contrary general rule [0], this phrase is mostly just nonsense.

[0] the original sense of Cicero’s “exceptio probat regulam in casibus non exceptis” (“the exception proves the rule in cases not excepted”, e.g., a posting ”entry permitted in daylight hours” implies a rule that entry is prohibited outside of those hours.)

Isn't it just because we have more recent ancestors with them and thus they match our sensibilities better? Bugs similarly look less appealing.

Native New Zealand animals are still going extinct, because of pressure from imported animals. Not just predation, also competing, and disrupting food chains.

There is also a https://xkcd.com/552/ common cause of climate change at the time.

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