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  • [Intro]

  • Every now and then, a story shows up on your Facebook page, your Tumblr dash, your Twitter

  • feed that just doesn't go away, because people keep arguing about it.

  • And arguments are fine, but they often tend not to reveal much in the way of data, or

  • context.

  • So with that in mind, SciShow wanted to weigh in on "The Great Walrus Haulout of 2014".

  • You've seen the pictures, probably, taken last month by a government biologist who counted

  • more than 35,000 Pacific walruses crowded together on Point Lay, a rocky barrier island

  • off Alaska's northern coast.

  • Depending on what online ecosystem you inhabit, you might have seen this picture shared as

  • a grim sign of global warming, or from the opposite perspective, as a normal event that

  • environmentalists have just hyped up.

  • Well, let's start with what we know - walruses can't swim for very long periods like seals

  • can, so they stop between feedings to rest on chunks of land or ice.

  • This is known as "hauling out" and it is a thing that walruses do, especially in late

  • summer and early fall.

  • What's interesting, and kind of weird about the Point Lay haulout, is that there are SO

  • MANY walruses resting together at the same place - it may be the biggest ever recorded.

  • And while it's been described as a walrus "flash mob", it is not nearly as fun as that.

  • Many of these walruses are females with young calves, and having thousands of animals, some

  • weighing more than a ton, in such close quarters can lead to battles over territory, accidental

  • tramplings, and the fast spread of disease.

  • In fact, deaths in these mass haulouts are common.

  • Now many media reports have quoted scientists as saying that haulouts are getting bigger,

  • and therefore more dangerous, because of global warming.

  • As sea ice melts, more walruses have to cluster together on land to rest.

  • But there's also been a backlash among your climate-change-is-not-happening crowd which

  • has pointed out - OFTEN IN ALL CAPS - that these things have been seen before.

  • Well yeah, sort of.

  • Most often the skeptics are citing a University of Alaska study from 1978 that estimated that

  • some 35,000 hauled out en masse that year, but that was an estimate made after the walruses

  • had moved on, gleaned mostly from how much land the walruses had disturbed, and how many

  • dead were left behind.

  • Since then, research into these events has become more regular and rigorous, and results

  • over the past ten years do seem to reveal a pattern.

  • The first large haulout on land was recorded in 2007, when 30,000 walruses were counted

  • on beaches on the Russian side of the Bering Strait.

  • And according to the U.S. National Marine Fisheries Service, this coincided with a loss

  • of sea ice in that part of the Arctic, that at the time, was unprecedented.

  • Then, in 2010, 20,000 walruses hauled out near Point Lay, and the following year, 30,000

  • appeared in the same place.

  • But these numbers haven't gone up every year - there were no huge haulouts in 2008 and

  • 2012, for example - years when, according to the Feds, there was enough sea ice for

  • all of the animals to rest on.

  • So the likelihood is we're going to be seeing more of these events in the future, but the

  • science behind them is more complicated that you can fit into one hundred and forty characters.

  • Another thing people like to argue about that's also being researched more than ever?

  • Cannabis.

  • By some estimates marijuana is now almost as prevalent as tobacco in many countries,

  • and on Monday, a new study from the University of Queensland laid out all of the research

  • that has been done on marijuana over the past 20 years, listing everything scientists have

  • learned, as well as what patterns they've observed but haven't been connected yet.

  • Among the conclusions, even through it's not chemically addictive like opiates, cannabis

  • has been found to cause what's known as a Dependence Syndrome - a persistent psychological

  • craving that can disrupt a person's thoughts and behavior.

  • This was documented in about one of every ten pot smokers across various studies, but

  • the risk was nearly twice as high - one in six - among adolescents.

  • Also, results show that regular cannabis users have double the risk of experiencing symptoms

  • of psychosis - a disorder often described as a loss of touch with reality, as well as

  • schizophrenia - a condition that causes things like disorganized thinking, delusions, and

  • hallucinations.

  • Now, this doesn't mean that pot causes these conditions, but the data do suggest that people

  • who are genetically predisposed to these disorders are more likely to have symptoms appear if

  • they smoke often.

  • Finally, there are some correlations that scientists have found while studying pot use

  • among teens, but so far they haven't found any direct link between the drug and these

  • observations.

  • Specifically, they found that adolescents who regularly use pot typically attain a lower

  • level of total education, suffer from intellectual impairment, and are more likely to use other

  • illicit drugs.

  • Now, these are all things that could have a number of social causes like poverty, access

  • to education, and family situations, so no causal link has been established at all.

  • But me?

  • We're talking about the health of my brain here, so I'm not taking any chances; it's

  • the only one I got, and I like to think it's working great on its own.

  • Thanks for watching SciShow News, brought to you by Audible - which is giving away a

  • free audio book to SciShow viewers.

  • You can go to audible.com/scishow, and download one of my favorite new science books of the

  • year, "What If?

  • Serious scientific answers to absurd hypothetical questions", narrated by my friend Wil Wheaton,

  • and written by the creator of XKCD, Randall Munroe.

  • Or, you know, practically any other book, for free, so go to audible.com/scishow.

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Walrus Flash Mob & 20 Years of Pot Research

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    joey joey に公開 2021 年 05 月 15 日
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