# Megafauna Extinction **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [April 19, 2017, 7:25pm UTC](https://boards.straightdope.com/t/megafauna-extinction/784803 "2017-04-19T19:25:31Z")\ **Posts on this page:** 3\ **Page:** 2
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [April 20, 2017, 8:28pm UTC](https://boards.straightdope.com/t/megafauna-extinction/784803/21 "2017-04-20T20:28:52Z")
> [@Ruken](#): > > Yes, your OP was obviously false without having read the paper. I did, however, read it in its entirety before posting. Did you? You were asked to back up your OP over eight hours ago and all you have to offer is “the bold part.” I cited the article. Look, my version doesnt allow copy and paste. The bolded part is the summation. If you read it, you can read the line that starts with : **Moisture Driven environmental changes appear to have played an important part in the late Quaternary megafaunal extinctions.** … However here is a summation of the article: > **[Megafauna extinction: DNA evidence pins blame on climate change](https://www.newscientist.com/article/dn27952-megafauna-extinction-dna-evidence-pins-blame-on-climate-change/)** > > Humanity has long been on trial for the demise of mammoths and other large mammals – new forensic evidence reveals the true killer \*The real culprit of extinctions is climate change (Image: Sergey Gorshkov/Minden) New forensic DNA evidence is painting a detailed picture of the death of the world’s megafauna – and it suggests that humans were not to blame. Ever since a giant sloth was uncovered more than 200 years ago, hinting at the former presence of a menagerie of prehistoric giant mammals – the “megafauna” – humans have been on trial for their extinction. And the prosecution’s case has been strong. … But the real culprit, he says, is climate change. Cooper and colleagues have simultaneously produced an unprecedentedly accurate map and timeline of changes in megafauna populations around Eurasia and North America, and precisely matched that timeline up with ancient climate records. It punches a hole in a key argument of the prosecution. This states that climate cannot have caused megafauna extinctions because it has changed so much over the past 60,000 years. There were lots of warm and cool periods – interglacial and glacial epochs, respectively. If climate change is the real megafauna killer, why did the animals survive those events only to die when humans turned up in their region? The new data show that they did not survive. Megafauna extinctions were actually relatively common during the past 60,000 years whether humans were around or not. Invisible extinctions To establish this, Cooper and his colleagues first compiled 10 years of ancient DNA work that has revealed a series of “invisible” extinctions. These are events involving two or more lineages with essentially identical skeletons but distinct genes – for example, two species of bison. If both lived in the same area in prehistory, one could have disappeared and we would not be aware of this just from examining the bones. Secondly, Cooper’s team created a new ancient climate record that, uniquely, can be accurately linked with the carbon dates from bones to show when particular extinctions happened. Usually the climate change and carbon dating timelines are independent and difficult to link together. But Cooper and his colleagues found a marine sediment deposit near Argentina that contains a record of past climates – and because it contains marine microfossils, these past climates can be tied precisely to carbon dates. Pulling everything together, the team was able to draw a picture that shows exactly what the climate was doing when various megafauna species vanished over the past 60,000 years. And a pattern emerges. “Climate is the thing that is constantly sending these species out through time without humans even being involved,” says Cooper. “That’s the bit that is really completely new.”\* So there is the author stating it clearly. > **[DNA evidence proves climate change killed off prehistoric megafauna](https://theconversation.com/dna-evidence-proves-climate-change-killed-off-prehistoric-megafauna-45080)** > > Animals that couldn’t adapt to rapid warming quickly succumbed. ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [April 20, 2017, 9:26pm UTC](https://boards.straightdope.com/t/megafauna-extinction/784803/22 "2017-04-20T21:26:15Z")
> [@DrDeth](#): > > I cited the article. Which does not support: > [@DrDeth](#): > > A new study has confirmed the primary cause of megafaunal extinctions[…] > [@DrDeth](#): > > Look, my version doesnt allow copy and paste. The bolded part is the summation. If you read it, you can read the line that starts with : **Moisture Driven environmental changes appear to have played an important part in the late Quaternary megafaunal extinctions.** … We scientists are tricksy and like to use the word “abstract”, but yes, here it is: [QUOTE=The Paper] Moisture-driven environmental changes appear to have played an important part in the late Quaternary megafaunal extinctions through alteration of environments such as rangelands, which supported a large biomass of specialist grazers. [/QUOTE] “Appear to have played an important role” is a far cry from “confirmed the primary cause”, especially for a paper that does not address other potential causes except in passing in the introduction. > [@DrDeth](#): > > However here is a summation of the article: These are summaries of a completely different article, 10.1126/science.aac4315 , published in 2015, which has fuck all to do with moisture extrapolation from nitrogen isotope ratios. That paper does, however, support the role of climate in megafauna extinctions. As does the one in the OP. Neither confirms it as the primary cause. It seems the authors think it is, and it may very well be. I expect they’ll continue to publish more evidence as they find it. My sole objection is the overstatement of the conclusions of the paper, stemming from a desire to promote good science literacy. We generally find results that are consistent with a hypothesis or which rule out other hypotheses. The paper cited in the OP does the first and not the second. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [April 20, 2017, 10:38pm UTC](https://boards.straightdope.com/t/megafauna-extinction/784803/23 "2017-04-20T22:38:56Z")
> [@John\_Mace](#): > > Can you quote the part of the Nature article that says that? > As do posts by he OP. > [@DrDeth](#): > > Right there in the bolded summary. I’m not surprised that you were unable to since it’s not there. [Previous page](https://boards.straightdope.com/t/megafauna-extinction/784803.md?page=1)