
Yellowstone Bears Eat 40K Moths a Day in August - curtis
https://www.yellowstonepark.com/things-to-do/bears-eat-moths-in-august
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dwills1
The summer of 2017 is going to be a bad year for the miller moth eating bears
of the Colorado Rocky Mountains (note: black bears only - there are no
grizzlies in Colorado). It seems there was a late freezing rain/frost that
killed many if not most miller moth grubs this year. I normally experience an
onslaught in the migration as I'm on their path from the eastern plains to the
mountains. Normal years I see dozens per night from June 1 to July 15, several
somehow squeezing into my house each day. This year there were essentially
zero miller moths.

~~~
kornish
Reminds me of going to summer camp as a child in Estes Park (north of
Boulder). Every summer, dozens of moths would inhabit the cabins, attracted to
kids' headlamps as we read books before bed. Kind of disincentivized people to
stay up reading, and we all went to bed straightaway. Can't imagine there not
being an armada of moths waiting in the wings.

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d-sc
Kinda cool to see this on hackner news. My landlord manages bears for the
greater Yellowstone area. So I have heard firsthand accounts about this.

The bears effectively scoop the moths from the rocks using their claws. It's
one of the most caloric dense foods they have.

~~~
MichaelMoser123
That was my question - the article also mentions bear managers. How do they
manage them? Do they hold meetings with the bears?

~~~
lpa22
From my experience with the Yellowstone bear managers I have talked to, they
attempt to connect with the grizzlies in their youth as cubs. As the cubs grow
older, the managers are able to promenade alongside them, join them at meals,
and even camp alongside them at night with their future bear families. It
establishes a human connection with the bears so they are one with the park.

~~~
pferde
Wow, I was under impression that a mama bear is quite protective of its cubs.
How do they get near without getting attacked and driven away?

~~~
avn2109
>> "How do they get near without getting attacked and driven away?"

The National Park service usually assigns the bear manager a herd of Jackalope
when camping with the bears. These Jackalopes distract the bears from the
presence of the humans.

While this approach is very effective in National Parks such as Yellowstone,
problems have recently arisen in other Grizzly-inhabited areas, notably near
the Bob Marshall and Scapegoat wildernesses, due to declining Jackalope
populations.

Efforts are underway to replace the Jackalope herds with a single baby moose,
or in some cases as many as three baby meese, but I can't vouch for the
efficacy of this technique.

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mathiasben
"While fat in the diet is not the best thing for humans, it is important to
bears." almost stopped reading after coming across this wise chestnut.

~~~
homosaphien1
America is paying the cost of demonizing fat and glorifying carbs in big way.
Obesity is a huge crisis. There is no solid science behind fat is bad theory.

~~~
yladiz
"It's the same word."

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almostApatriot1
there was a good issue of National Geographic dedicated to Yellowstone that
covered this last year:

[http://www.nationalgeographic.com/magazine/2016/05/yellowsto...](http://www.nationalgeographic.com/magazine/2016/05/yellowstone-
national-parks-part-2/)

Basically, the grizzlies there build up on moths and nuts. The moths are 65%
body fat.

~~~
hcrisp
Also BBC had a similar episode on moth-eating grizzlies:

[http://www.bbc.co.uk/programmes/p00377yp](http://www.bbc.co.uk/programmes/p00377yp)

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WheelsAtLarge
Findings like this is why I find it very unpleasant when people start talking
about destroying whole species because they are pests to humans.

The latest one I've read about is the idea that we need to get rid of all
mosquitos. They are pests to us but I wonder how many other species depend on
them for food and how will the mosquito's extermination affect the web of
life.

~~~
revelation
We know what happens: evolution. The idea that the whole thing will totally
collapse because you made one change is ridiculous and frankly utterly
unsupported by the evidence, not least our understanding of this poor
optimization algorithm driven by random chance.

I frankly always find these comments unpleasant because they seem to come
exclusively from people sitting in some air-conditioned building miles away
from a full 5 m^2 trees that they got to riding a 2 ton behemoth on tarmaced
streets that casually reaches speeds no animal ever could powered by the
remains of dinosaurs. Yeah I wonder how that affected "the web of life". It's
a fashionable form of NIMBY except these people are not arguing from a
position of naked self-interest but ignorance.

~~~
Radim
Sure, the nature will adapt, but will humans? For us, it's not a zero sum game
of universe-wide optimization. We have skin in the game, so to speak.

Mandatory George Carlin link: "The planet is fine; humans are fucked"
[https://youtu.be/YawTvnyoqbU?t=77](https://youtu.be/YawTvnyoqbU?t=77)

~~~
WheelsAtLarge
Well said. I've heard this before,"Destruction by many cuts will eventually
kill us." I think you can apply this to the way we treat our environment.

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nraynaud
[https://www.youtube.com/watch?v=iSFMObszwHw](https://www.youtube.com/watch?v=iSFMObszwHw)
for people like me who did not understand at all how they do it.

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ugh123
So the way they come to the 40K number is since each moth is about 1/2
calorie, and the bear requires at least 20k calories a day, then they must eat
40k moths/day. Hmm

~~~
maxerickson
Someone counted the moths in scat.

~~~
maxerickson
Seriously, counting moths in scat contributed to the estimate:

 _White made that estimation by watching grizzlies with a scope for up to 14
hours per day, while writing his dissertation on the animals at Montana State
University-Bozeman. He also counted how many dead moths he could find in each
bear “scat,” or pile of poo, and multiplied that by the number of times these
bears defecated._

[http://www.newsweek.com/grizzly-bears-can-eat-40000-moths-
da...](http://www.newsweek.com/grizzly-bears-can-eat-40000-moths-day-400281)

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schwarzrules
Could protect the moth population with a more liberal policy to provide bears
access to picnic baskets...

~~~
pferde
Not if Ranger Smith has something to say about it.

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briga
I don't think it's just the Yellowstone area. In Jasper I've seen bears doing
the same sort of the rock-flipping scavenging. The sheer number of moths they
eat is pretty surprising though, I never would have suspected bugs to be such
a big food source for bears.

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Mothra555
My question is this. Why would pesticides on the farms that wipe out a lot of
these moths be causing a problem?

The bears were there before the farms. If the farms are creating a lot of new
moths that weren't otherwise there, wouldn't the pesticides be bringing things
back into equilibrium?

I am really against using pesticides and I try to eat only organic products,
but I am just wondering why no one else seems to be talking about this. Those
mass quantities of moths being there isn't natural in the first place.

~~~
stinos
_The bears were there before the farms. If the farms are creating a lot of new
moths that weren 't otherwise there,_

Another possibility is the moths were there before the farms as well, and the
land they lived on now happens to have been turned into farmland. If that is
the case than it's not as likely anymore that pesticides would bring an
equilibrium. Maybe there were even more moths before it the land was one huge
monoculture. (just spraying ideas here, I don't know what kind of land moths
prefer nor if it really is a monoculture there)

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BigJono
That seems like an extraordinary claim. If the bears were eating moths for 10
hours straight, they'd have to catch and consume more than one moth every
second to hit that number... I must be vastly underestimating the amount of
moths in these caves or the amount they move around.

~~~
hasenj
Why would assume they would be eating them one by one?

~~~
dahart
The article only describes them being eaten one by one, and does not describe
how massive numbers are being eaten at once. The question seems reasonable--
how is the number 40,000 arrived at? Do you know? The article feels hand-wavy
and light on sources and details. This feels to me like the kind of number
that someone arrived at by assuming that a bear might eat its entire caloric
intake in moths and then dividing 20k calories by 0.5 per moth, so it _could_
be up to 40000 moths.

There's a sign on waterless urinals all over the place that claims it saves
"up to" 40000 gallons of water per year. It'd have to be running non-stop
24/7/365 for that to be true. There's an ad that I hear playing on NPR
sometimes about a container rail train that gets "up to" 500 miles per gallon.
Just keeping the lights on uses more gas than that. These "statistics" don't
pass the smell test, and this story feels similar to me.

~~~
foobarian
> Just keeping the lights on uses more gas than that.

Can you elaborate on this?

One gallon of diesel = ~41kWh. Assuming 30% conversion efficiency that gives
us 14kWh. Assuming a 50mph speed to traverse 500 miles means we need to keep
the lights on for 10 hours, giving us a power budget of 1.4kW. I don't know
what kind of lights locomotives carry but that seems like an awful lot.

~~~
slededit
locomotives have two headlamps around 200W, and two ditch lamps (the ones at
the bottom near the rails) of 350 watts each. That's 1.1KW already, plus any
interior lighting and conversion losses from the diesel genset.

Also average freight train speed is tracked and its consistently less than
25mph:

[https://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/pu...](https://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/publications/transportation_statistics_annual_report/2008/html/chapter_03/table_03_04_08.html)

Note however that fuel efficiency is almost always given in mpg per freight
ton, in which case the power usage of the lights would be amortized over the
considerable mass of the train. >400 mpg per ton is not uncommon on a train.

~~~
foobarian
Cool info, thanks.

It occurred to me that elevation change could have huge impact on those
calculations. More back of the envelope stuff: a 5k ton train requires 13.6kWh
to ascend 1m. If such elevation changes are common that would quickly dwarf
small values like the power consumption of lights.

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rMBP
> While fat in the diet is not the best thing for humans

Why does the article say this?

~~~
WheelsAtLarge
We're constantly hearing how fats are bad for us and we should eat a low fat
diet. The article is overstating that fact. A better statement should say that
the overeating of fats is bad for us. Eating NO fats would certainly be bad
for people. Everything has to be eaten in moderation.

~~~
chillwaves
Do you have evidence to support this claim?

~~~
WheelsAtLarge
There are some essential fatty acids that the body can't make but needs. So,
no fats is a problem.

[https://en.wikipedia.org/wiki/Essential_fatty_acid](https://en.wikipedia.org/wiki/Essential_fatty_acid)

~~~
chillwaves
I was referring to the "fats are bad for us" part.

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undersuit
I've got to call out the false information in the article: "While fat in the
diet is not the best thing for humans".

When will the anti-fat brigade stop?

Still an insightful look into possible environmental cycles we've missed
because we have devastated the North American bear populations for centuries.

~~~
slimsag
I have no clue, so could you point out why fat in the human diet is good (or
not bad)? I'd like to learn.

~~~
cropsieboss
Bears, like true omnivores, eat bugs and fruits and animal flesh and grass and
practically anything to fill their bellies. Bears also, like true omnivores,
can't get atherosclerosis from things they consume.

Humans, feeding on primarily fat based diet get atherosclerosis very often.
Best epidemiological/history research on that topic is done on Inuits where
remains of children showed atherosclerotic plaques in the vessels - their
diet, although not ketogenic, contained mostly animal fats and proteins. Other
mechanistic studies proved that direct causal mechanism exists but the same
thing happens also with sugary diet, or essentially any diet with a caloric
surplus (highest effect of course with highly caloric diets or diets rich in
cholesterol over long timespans).

Essential fatty acids (omega-3 and omega-6), on the other hand, are abundant
in animal flesh (if we ignore plant oils). Human reliance on these sources
definitely implies we are omnivores but with a certain complex twist.

Given the young age of nutrition science, lack of personalized methods, and
flawed epidemiological studies (for example, epidemiological studies
condemning meat and dietary cholesterol ultimately fail, on the other hand,
studies showing that dietary cholesterol has no effect on basline cholesterol
are methodologically flawed), a skeptic would conclude we still know little
when it comes to long consistent living and the effect of diet on health. We
do know a lot about intervention on sick people though. Practically any diet
that is more healthy than a diet sick people practice works, best one being
the one with highest nutrient to calories ratio (foods that have huge volume
but low calories tend to have that characteristic and its mostly just plants -
hard to overeat and create a caloric surplus), which is a plant-based diet.
Still, it's questionable how this works long term (what's the source of fatty
acids? where's B12 etc.).

~~~
nicholas73
I've read studies that discuss excess cellular energy as the cause of
metabolic disease, but are there any studies on athletic people eating high
calories over long periods? That is, would Michael Phelps' 10k calorie per day
cause a problem, even if he uses all 10k? Because there would be spikes unless
one is meticulous about eating small meals over the day.

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MightyPowerful
The bears would probably eat other stuff but those aren't readily available
due to human activity. (Like introducing giant wolves not native to the area.)

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r00fus
"As importantly, the moths provide a crucial food source in the face of
declines of other bear foods"

Seems to me the fact is that bears usually eat other stuff but those aren't
readily available (likely due to human activity).

~~~
quadrangle
That "seems to me…" bit should be presented as just a hypothesis. It may be
right, but I'd have no basis to even lean toward assuming so.

