What Happened to Ancient Megafauna?

https://nautil.us/what-happened-to-ancient-megafauna-713371/

by jnord • 2 years ago

86 96 2 years ago

This is not about assigning blame, says Svenning. “People who lived thousands of years ago never had access to the full picture. These things took place across long time scales and big spatial scales over which no one had an overview; whatever people did, it was difficult to see the consequences. Plus, of course, people just had to survive the best they could.” - lol even

linearrust• 2 years ago

Defined as large-bodied terrestrial mammals with a mean adult body mass of 2,200 pounds or more, today’s remaining megaherbivores comprise the likes of elephants, rhinoceroses, giraffes, and hippopotamuses.

Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction?

I think work over the past few decades has rather convincingly demonstrated that humans had a pretty substantial part in the extinction

A substantial part in the extinction? What does that mean? The extermination of the buffalo in the US required industrial scale resources ( guns, railroads, etc ) along with the migration of millions of europeans and habitat loss ( via farming ). It was a conscious and intentional effort. Are they claiming something similar happened throughout much of europe, asia and americas more than 50,000 year ago?

“When we restore forests, we can’t just think about the trees,” he says. “We must think about the animals that belong there.”

This. The most devastating blow for the buffalo, wolves, bears, etc was habitat loss. It was ultimately what did them in. Did ancient hunter-gatherers alter their environment to such a degree to wipe out herds of giant animals from entire continents?

I have a hard time believing that hunter gathers in tiny tribes traveling on foot with primitive weapons could have hunted and wiped out entire species of large animals from continents. I wish they would give more specifics.

mr_toad• 2 years ago

Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction?

One theory is that they gradually adapted as humans developed.

Once humans spread out to other continents the change was too rapid for the megafauna on those continents to adapt.

simonh• 2 years ago

Also there were megafauna extinctions in Africa, just over a longer period of time. Then humans expand out of Africa, and within a few tens of thousands of years most of the extra-African megafauna are gone.

nkrisc3• 2 years ago

Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction?

Consider that African megafauna have co-existed with early hominids and eventually humans for millions of years. They may have simply adapted to human predation successfully enough to survive, as one factor.

Whereas in North America and elsewhere you have the sudden (on the evolutionary time scale) arrival of Homo Sapiens who are likely already very skilled and advanced hunters among a population of prey animals that have never experienced such a predator.

It’s also possible that in tandem, climate change was less severe in Africa than elsewhere over the last 50k years.

BurningFrog2• 2 years ago

Right, we're a native species to Africa, so its whole ecosystem evolved with us.

I think of this when I hear about "poachers" killing animals in African nature reserves. How often is that hunter gatherers who been there for thousands of years, and whose hunting is/was really part of the ecosystem?

b1122• 2 years ago

On some islands off the Northern coast of BC, there are dwarf deer that locals just walk up to, and smack on the head with a baseball bat. Right or wrong, it sort of highlights the point.

lawlessone• 2 years ago

Consider that African megafauna have co-existed with early hominids

It is this imho Animals in Africa are more scared by the sounds of people than lions.

https://www.nhm.ac.uk/discover/news/2023/october/human-voice...

And the bigger ones like Hippos are hyper aggressive to humans, allegedly they kill more people than any other African animal.

AlotOfReading5• 2 years ago

They don't know any particular specifics. Our understanding of human organization during the late pleistocene and early Holocene is poor, bordering on non-existent. However, I don't find it particularly hard to imagine humans as a major factor, even if I have some doubts about this particular argument.

First, you have to understand that about the late quaternary extinctions, we know not all quaternary extinctions were anthropogenic. Ecosystems were experiencing a lot of different stressors around that time, and by the time extinction actually happens there may have been only small populations left for centuries or millennia. Ecological resilience is also a bit of a funny thing. You might think that you make 10 species extinct has 10x more impact than just 1 extinction, but there isn't a linear relationship. In many ecosystems, there's very little impact from most local extinctions as the graph thins out until all the systemic resilience is gone and the whole thing suddenly collapses into a new state. Did that proximate cause(s) of the last extinction cause the rapid shift?

Fantastically deadly hunters like humans that are specialized to megafaunal hunting being able to push the most vulnerable and stressed parts of the ecosystem over the edge isn't an obviously absurd argument to me.

alfiedotwtf2• 2 years ago

Thinking out loud… I wonder if it could still be true based on the fact that the larger the animal, the longer the gestation period.

For small animals like rabbits, it’s about 30 days - so their chances of “multiplying like rabbits” is obvious - you’re not going to wipe out rabbits faster than the supply.

As you move up the size scale, the gestation period gets longer and longer, and each kill gets harder to replace (wales come in at around 18 months!). Kill a mega-sloth and its chances of species survival dramatically drop!

shawn_w• 2 years ago

The number of offspring in each litter tends to drop with increasing size, too.

deadbolt• 2 years ago

The most devastating blow for the buffalo, wolves, bears, etc was habitat loss.

Wasn't the most devastating blow to Buffalo the campaign by settlers to slaughter them, since they were important to the native Americans?

daemonologist• 2 years ago

True for the American bison (as far as I know), but there used to be a bunch of species in Eurasia which went extinct or had their range dramatically reduced as part of the broader extinction of megafauna discussed in the article.

dghughes• 2 years ago

I think the word buffalo really confuses people.

Bison are in North America while buffalo (small b) are in Asia and Africa.

Wasn't the most devastating blow to Buffalo the campaign by settlers to slaughter them

I hope everyone in the city of Buffalo, NY are OK lol

Earw0rm• 2 years ago

Not all megafauna are herd animals on the scale of American buffalo. Others were limited to smaller areas or less numerous to begin with, and the ones that survive are probably those that started off most numerous. African elephants are hanging on by a thread, relative to their original number they're down something like 98%.

Africa is also _huge_ - around four times the size of the entire continental USA - and suffered perhaps less during the Ice Ages than Northern America or Eurasia, where megafauna would have been squeezed by both the ice - and associated climate changes further south - and a hungry and increasingly innovative human population.

TeMPOraL• 2 years ago

I have a hard time believing that hunter gathers in tiny tribes traveling on foot with primitive weapons could have hunted and wiped out entire species of large animals from continents

One thing humans could was starting fires that would drive many animals into a designated killbox, among other ways of "cheating". Humans were uniquely capable (at this size scale, at least) to both hunt species in excess to their need and cause outsized damage to their habitat in the process.

kjkjadksj3• 2 years ago

The default is to outpace your need. Imagine if we evolved to somehow hunt just enough meat. There’d be some of us with less efficient systems for controlling that behavior that end up starving while they think they are bringing in enough food. Thats no good for reproductive fitness. Overshooting on the other hand is good.

Another factor, symbiotic relationships tend take much longer to evolve that carefully balanced relationship between symbiont and symbiont. Parasitic relationships tend to evolve sooner and its also not uncommon the parasite overshoots and kills off its own host.

trhway• 2 years ago

I have a hard time believing that hunter gathers in tiny tribes traveling on foot with primitive weapons could have hunted and wiped out entire species of large animals from continents

last mammoth died just 4000 years ago on an Arctic island - i.e. without humans they survived far longer even in pretty harsh conditions.

christkv• 2 years ago

They are guessing. Probably a ton of compounding factors rather than a single one. Ice age (probably a big one for anything not in Africa), hunting, habitat compression, food competition, etc. I'm also guessing :)

nihzm• 2 years ago

I have a hard time believing that hunter gathers in tiny tribes traveling on foot with primitive weapons could have hunted and wiped out entire species of large animals from continents. I wish they would give more specifics.

This made me recall having read something related to it in the book Sapiens [1]. Indeed, I went looking and quoting from chapter 4

All the settlers of Australia had at their disposal was Stone Age technology. How could they cause an ecological disaster? There are three explanations that mesh quite nicely.
Large animals – the primary victims of the Australian extinction – breed slowly. Pregnancy is long, offspring per pregnancy are few, and there are long breaks between pregnancies. Consequently, if humans cut down even one diprotodon every few months, it would be enough to cause diprotodon deaths to outnumber births. Within a few thousand years the last, lonesome diprotodon would pass away, and with her the entire species. [...]
The second explanation is that by the time Sapiens reached Australia, they had already mastered fire agriculture. Faced with an alien and threatening environment, they deliberately burned vast areas of impassable thickets and dense forests to create open grasslands, which attracted more easily hunted game, and were better suited to their needs. They thereby completely changed the ecology of large parts of Australia within a few short millennia. [...]
A third explanation agrees that hunting and fire agriculture played a significant role in the extinction, but emphasises that we can’t completely ignore the role of climate. The climate changes that beset Australia about 45,000 years ago destabilised the ecosystem and made it particularly vulnerable. [...]

So the extinction was on a very different timescale from your buffalo example, but an extintion nonetheless. In the ellipses the book briefly points to some evidence to support these theories.

[1] https://en.wikipedia.org/wiki/Sapiens:_A_Brief_History_of_Hu...

graemep• 2 years ago

Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction?

Elephants and rhinos do survive in Asia.

throwup238• 2 years ago

I'm still digesting the full paper [1] but it looks like the gist is that when you put all the previously published data together, the timing of megafauna extinction statistically lines up with human arrival better than climate change.

The most important pieces of evidence they seem to look at is fungal spores in fossilized poop and sedimentary ancient DNA:

Further, other studies show contrasting patterns. For example, a sedimentary ancient DNA (sedaDNA) study from the Yukon shows strong megafauna decline between 21 and 14,500 years ago, prior to the loss of the mammoth steppe biome and the Younger Dryas. In addition, as already mentioned, many extinct megafauna species have last occurrences in the Early or even Middle Holocene, that is, during the relatively stable climate of the Holocene, meaning that a climatic cause for their extinction is unlikely given their previous survival through numerous, massive climatic shifts throughout the Pleistocene, including long and warm interglacial periods.
An increasing number of studies look at local and regional dynamics in the overall abundance of large herbivores at high spatiotemporal resolution using dung-associated fungal spores. Many of these are able to pinpoint declines to timeframes where the climate was stable, for example, North America ~14–13,000 years ago, prior to the Younger Dryas cooling, and 41,000 years ago in Australia at a time of no substantial climate change

These techniques are still very new and they're so sensitive that they should be taken with a grain of salt, sedaDNA especially since it amplifies tiny snippets of DNA found in permafrost. We assume permafrost behaves like an annually laminated sediment but that's controversial and archaeology/paleontology have had plenty of problems before with DNA snippets and contamination.

[1] https://www.cambridge.org/core/journals/cambridge-prisms-ext...

cryptonector2• 2 years ago

This guy (https://www.youtube.com/@Antonio_Zamora) makes a very solid argument that in the Younger Dryas a meteorite impactor hit the ice sheet over the Great Lakes, sending huge ice chunks flying that created elliptical craters that then quickly refilled that are called the Carolina Bays, and which are ubiquitous in the South East, and which point back at the impact point(s) (I think he says there were two impact points) in Michigan. The amount of energy delivered by all those ice chunks seems to have been several megatons (of TNT) per square mile. Enough chunks were ejected, and carolina bays formed, to have likely caused an extinction event.

AlotOfReading5• 2 years ago

There's a real danger in getting misinformation from YouTube channels. The Younger Dryas Impact Hypothesis has been extensively refuted multiple times. The latest such paper (https://doi.org/10.1016/j.earscirev.2023.104502) is pretty exhaustive in exploring the history of these ideas and how they fall short.

alfiedotwtf2• 2 years ago

YouTube is like the anti-Wikipedia. It’s easy to create videos and the only check are comments buried 200 comments down

hnfong• 2 years ago

In your link, the first words of the abstract is:

"A series of publications purport to provide evidence that..."

So even published papers contain such "misinformation", it isn't specific to Youtube. I have no training in the areas of archaeological evidence, so I don't know what to make of the paper, but it looks like people are just arguing about evidence of whether there was an asteroid impact.

It's interesting though that the title of the paper is called "Complete Refutation" of the hypothesis and not of the evidence. If you're nit-picky enough you'd notice that the YDIH isn't a "scientific" hypothesis per se since hypotheses about what happened in the past doesn't really give testable predictions, and actually what they did in the paper was to refute all the evidence of the hypothesis -- but it seems to me it's still theoretically possible for new evidence to come up that definitely supports YDIH.

Also, AFAICT this only rules out the asteroid impact. It still doesn't rule out the possibility that the abrupt climate changes during the Younger Dryas causing stress to the megafauna population, which presumably is another thing.

cryptonector2• 2 years ago

You clearly didn't even take a look. Zamora is not a run of the mill YouTube loony but a published academic. I'll look at the paper you linked, but you should look at Zamora's papers too.

defrost4• 2 years ago

The linked nautil.us article is a one sided poor summary of what is still an ongoing debate with strong beliefs on either side.

Two people are quoted:

* Jens-Christian Svenning, director of the Danish National Research Foundation’s Center for Ecological Dynamics in a Novel Biosphere at Aarhus University. He’s also the lead author on a recent paper published in Cambridge Prisms: Extinction that argues it was not climate change but rather human hunting that caused the extinction of most megaherbivores over the past 50,000 years.

and

* Felisa Smith, a conservation paleoecologist and professor at the University of New Mexico, believes that the human impact on megafauna extinction is no longer up for debate. “I think work over the past few decades has rather convincingly demonstrated that humans had a pretty substantial part in the extinction,” says Smith.

and ... no other views are given.

This, currently, isn't a slam dunk for one side, there are strong voices on the other side who can cite examples where humans certainly ate megafauna but not, apparently, enough to wipe them out and also point at concurrent pockets (eg: Tasmania) where there were megafauna, as yet no humans, and still the megafauna died out.

Xen9• 2 years ago

Darwin (1) near consistently included each and every argument & counter-argument to the point where it becomes boring and unreasonable to go any further (2) was absolutely explicit of what was NOT included to the point that there were redunant remarks about that!

---

The view of Smith is laughable, for the human population has changed by more than few orders of magnitude since those times.

Yet it would be plausible that a global MF ecosystem was distrupted somehow.

Another possible reason megafauna died: they eat plants and grew on top of an ecosystem where there was not much competition for plants, and then an increase in efficiency of bacteria, bugs, invertebrates and other compact herbivore species in consumption of the limited amount of plant food pulled the legs under them. Whales were not herbivores, and possibly therefore not subject to same mechanisms (though saying this sort of ruins the metaphor of pulling legs from underneath).

arthurbrown• 2 years ago

Could you provide some more details about the Tasmania example? Seems humans reached Tas "at least" ~40,000 years ago from my simple searching, which isnt too far off from the generalised 50,000 mentioned in the article.

Which species went extinct before then?

https://www.sciencedirect.com/science/article/pii/S030544032...

defrost4• 2 years ago

    This alternative scenario of extinction is even more relevant in areas where climate was the only plausible driver of megafauna extinctions—in areas where there was an absence of temporal human-megafauna coexistence such as in Tasmania

Climate-human interaction associated with southeast Australian megafauna extinction patterns

Nature Communications, 22 November 2019 https://www.nature.com/articles/s41467-019-13277-0

Discussed by authors: https://theconversation.com/did-people-or-climate-kill-off-t...

A better paper than your find that directly addresses the gap|overlap in Tasmanian megafaune|human record is:

Man and megafauna in Tasmania: closing the gap Quaternary Science Reviews (Jan 2012)

https://sci-hub.ru/10.1016/j.quascirev.2012.01.013

Some megafauna were still present when humans arrived (at least two taxa) .. but most had already disappeared from the record and (IIRC) no megafauna bones found in human sites (indicating Mmmm, lunch).

xhkkffbf• 2 years ago

Here's my question: if humans caused megafauna extinction, why did this not happen in Africa? That's where many of the megafauna continue to live. But humans came from Africa.

slibhb• 2 years ago

The theory is that African megafauna evolved alongside humans, learned to fear them, and developed strategies to avoid them. Whereas other megafauna didn't, so when humans left Africa, they were defenseless.

VeninVidiaVicii• 2 years ago

Somewhat speculative of course—the extant megafauna you’re referring to are somewhat endangered and but also don’t represent great sources of usable materials such as meat or skins. Additionally, many are quite dangerous — rhinos, hippos, and elephants to be specific.

ds_opseeker• 2 years ago

Another theory-- there are lots of places in Africa where people cannot live due to disease (without modern medicine). This creates refuges for wildlife.

throwaway57522• 2 years ago

I mention this only to add to your informative post. Humans almost drove whales extinct because their rendered fat produced less fat for lamp fuel, and they are substantially pelagic. We almost drove bison extinct in NA in a matter of decades. We are driving massive numbers of species across trophic levels extinct, right now https://www.theguardian.com/environment/2023/dec/29/us-anima...

It isn't a choice, climate change related habitat changes probably contributed - which is also extremely pertinent today - but when you find the extinct species bones in human habitats it's a fair sign we were a contributing and possibly decisive cause.

jccooper• 2 years ago

Whales and bison were subject to very modern techniques. While sailing whalers did stress whale populations, it was the steam launch and exploding harpoon that really did the whales in. Bison were destroyed with rifles, which are new in themselves, but the mass-slaughter behavior was enabled by rail transport. Plus they were plenty stressed by competition with cattle, bred for rail transport, and enclosure of the prairie by barbed wire.

Earlier lithic-technology subsistence whale and bison hunting doesn't seem to have been a big problem for either. I won't say that early human hunting didn't contribute to or cause mega-fauna extinctions (in fact, it seems quite likely) but that's not highly analogous to these more recent events.

karaterobot• 2 years ago

Thank you for saying this, I had the same thought. I am not a researcher in this area, but it's one I pay attention to, and I have not gotten the impression that the question is as settled as this article makes it seem.

Actually, what I should say is that I always read articles or watch videos that make it seem like a slam-dunk case from either side (human predation or climate change), which I interpret as a) signs of a contentious ongoing debate, and b) a suggestion that the real answer will be found to be a complicated interaction between these factors, and many others as well. As it is with most things, frankly.

darby_nine2• 2 years ago

You're not wrong but it's kind of absurd to expect slam dunk evidence of any kind of causal link in the archaeological record.

defrost4• 2 years ago

I don't expect slam dunk evidence and that'd be an absurd projection onto anybody familiar with the paleontological record.

I do, perhaps foolishly, expect articles in the science domain, even if PopSci, to not behave as if a single recent paper in a field is the only paper of note and one that definitively sews up an ongoing debate.

I'd hope such an article would at least mention other equally recent papers that have both parallel and opposing views.

kleiba3• 2 years ago

One idea I had a while back is this: with all our modern technology in stem cell research, gene modification and cloning, shouldn't it be possible to recreate actual living clones from prehistoric dinosaur DNA? I mean, sure, these giant wild animals could potentially become dangerous, but how about we confine them to a remote island or so?!

alserio2• 2 years ago

Good idea, like a park of something? The most difficult part would be naming it. You could go for something like Cretaceus Park, but it doesn't sound too good.

knifie_spoonie• 2 years ago

Billy's Cloneasaurus Park

kleiba3• 2 years ago

Oh, a park! Like, where people come and can look at the creatures for an entrance fee? Yeah, sure why not. Also like your naming idea, perhaps something a little catchier?

ainiriand• 2 years ago

I believe that you will only need one IT person and I would like the job!

defrost4• 2 years ago

UiX is key, haz u 3D file interface for UNIX system?

Recursing• 2 years ago

See https://en.wikipedia.org/wiki/De-extinction , https://en.wikipedia.org/wiki/Revival_of_the_woolly_mammoth and https://en.wikipedia.org/wiki/Pyrenean_ibex#Cloning_project

A huge issue with "Jurassic Park" style cloning is that old DNA degrades very quickly

djmips• 2 years ago

One thought I always had about reviving prehistoric animals is that I feel we've come to understand that animals live in a symbiotic relationship with microorganisms. Some even have specialized diets. Then there's the so called epigenetics. So besides the missing microbiota there may be other factors that are missing and can't easily be recreated.

morkalork• 2 years ago

Coming from the other direction, there's a book about all the plants that were dependant on megafauna for processes like seed dispersal that are sorta hanging around still called "The Ghosts of Evolution".

chucke1992• 2 years ago

It died.

Keysh• 2 years ago

The (Nautilus) article is confusing in the way it conflates "megaherbivores" (herbivores weighing more than 1 [metric] ton) and "megafauna" (any animal, regardless of what it eats, weighing more than 45 kg[1]).

Also: "Giant ground sloths, musk oxen, and short-faced kangaroos: All have gone the way of the dodo" -- A) Of those three animals, only the giant ground sloth was big enough to qualify as a megaherbivore; and B) musk oxen are very much not extinct!

[1] Which I assume is a translation of an older definition using 100 lb as the lower limit.

fuzzfactor• 2 years ago

I always figured they were delicious.

imp0cat• 2 years ago

They probably weren't THAT delicious, but the portions were huge! ;)

rfwhyte• 2 years ago

It's always seemed patently obvious to me that humans were the primary cause of megafauna extinctions. First and foremost because the timing of extinctions aligns so closely with the arrival of humans in a given region, but also because the climate has changed dramatically over the past few million years or so, with cooler or warmer periods happening frequently over geological timespans, yet we don't see similar extinction events happening around climatic cycles / events other than those that happen to align with the arrival of humans in a given region. The Mammoths of North America for example survived numerous cycles of warming and cooling, some far more drastic than the most recent ice age and subsequent warming period, so why was it only the most recent one that caused their extinction? We already have control data for the effect climate had on megafauna populations, the only variable left is us humans.

What Happened to Ancient Megafauna?

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