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Yellowstone Bears Eat 40K Moths a Day in August
- deleted 9y ago[deleted]
- almostApatriot1 9y agothere was a good issue of National Geographic dedicated to Yellowstone that covered this last year: http://www.nationalgeographic.com/magazine/2016/05/yellowstone-national-parks-part-2/ http://www.nationalgeographic.com/magazine/2016/05/yellowsto... Basically, the grizzlies there build up on moths and nuts. The moths are 65% body fat.
- hcrisp 9y agoAlso 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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- BigJono 9y agoThat 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.
- almostApatriot1 9y agothe moths hide under rocks during the day because it is too hot
- WheelsAtLarge 9y agoI suspect they find the moth's hiding places and eat them at will by the mouth fulls.
- hasenj 9y agoWhy would assume they would be eating them one by one?
- dahart 9y agoThe 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.
- ivanbakel 9y ago>The article only describes them being eaten one by one From my reading, the article barely describes them being eaten at all. The black bear "licking moths off his arms" might reasonably be collecting a few at a time. Where does your interpretation of "one by one" come from?
- tootie 9y agoI remember the gypsy moth invasion of the 1980s. You could peel a few thousand off of one tree in my backyard. I have no trouble believing a determined bear could eat 40,000 a day if they were congregated like that.
- foobarian 9y ago> 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.
- Scriptor 9y agoI think the article is talking about the entire bear population eating 40k each day.
- elijahparker 9y ago"It is estimated that some 40,000 moths per day can end up in the stomach of a hungry bear." Seems to imply up to 40k/bear, but doesn't give much more for details. It mentions moths are about a half a calorie each, so just from the moths a bear can consume 20,000 calories/day.
- taeric 9y agoDepends how you read it. If you take the numbers to be each moth will end in the stomache of a single bear, it still works. Yes, that is a silly way to see it, since bears probably don't share meals. But it does work with the numbers.
- ryanplant-au 9y agoI'd read it as implying the opposite: that there are 40,000 moths out there who will wind up in a bear's stomach tonight. Like "some 40,000 people per day are hit by a car"; you wouldn't take that as meaning one car hit 40,000 people.
- codelord 9y ago"That means that 20,000 calories of just moths per day can be consumed by "A" rock-turning grizzly bear." How can you possibly read this and think this was about the whole bear population?
- komodo 9y ago"some 40,000 people per day are hit by "A" car". How can you possibly read this and think this was about the all cars on the road? Sorry for being cheeky but the parent literally just addressed your question.
- dboreham 9y agoThey eat them in industrial quantities. Moths are very prevalent here. I vacuum up around 10 a week just in my living room.
- saryant 9y agoThey used to fill my basement when I lived in Wyoming. Huge swarms of them. So, I don't find the stat too far-fetched.
- undersuit 9y agoI'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 9y agoI have no clue, so could you point out why fat in the human diet is good (or not bad)? I'd like to learn.
- fiblye 9y agohttp://knowledgenuts.com/2015/01/21/how-to-starve-to-death-while-stuffing-yourself-with-rabbit-meat/ http://knowledgenuts.com/2015/01/21/how-to-starve-to-death-w... A certain degree of fat is essential. People have been reported to actually starve on very high protein/very little fat diets.
- Laforet 9y agoThe linked article actually describes limitations with low carbohydrate diets. Attempts to make up yhe caloric deficiency with only protein is bad as the body struggles to keep nitrogen balance. Given plenty of carbohydrates, it is possible to survive long term on very limited supply of essential fatty acids as well as proteons.
- ue_ 9y agoLow carbs and high fat/protein is the essence of the keto diet, which I've heard has worked out well for some people.
- toomuchtodo 9y agoWorks incredibly well. https://www.reddit.com/r/keto https://www.reddit.com/r/keto
- rMBP 9y ago> While fat in the diet is not the best thing for humans Why does the article say this?
- alyx 9y agoFourth paragraph.
- thaumasiotes 9y ago>> Why does the article say this?
- WheelsAtLarge 9y agoWe'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 9y agoDo you have evidence to support this claim?
- WheelsAtLarge 9y agoThere 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 9y agoI was referring to the "fats are bad for us" part.
- WheelsAtLarge 9y agoFindings 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 9y agoWe 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.
- chillwaves 9y agoBut won't you please think of the mosquitoes!
- PhasmaFelis 9y agoIt's just as silly to assume that everything will be fine if we lose one species as it is to assume that everything will collapse. These questions need to be asked and studied, not just dismissed with a sneer either way.
- blackoil 9y agoEvolution works for natural slow changes over thousands of years and not against sudden disruptions. There had been multiple ELEs.
- Radim 9y agoSure, 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
- d-sc 9y agoKinda 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 9y agoThat was my question - the article also mentions bear managers. How do they manage them? Do they hold meetings with the bears?
- lpa22 9y agoFrom 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.
- sirtaj 9y agoIsn't there a concern that this will desensitise them to humans, or is it just assumed that it'll happen anyway because of all the tourists?
- Athas 9y agoBeing desensitised to humans is not necessarily a problem. The problems occur if humans are seen as threats (which they probably will if they are unused to humans), or more importantly, if humans are seen as a food source. That's when things easily become dangerous. As long as the bear managers don't bring snacks to their meetings, it should be OK.
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- schwarzrules 9y agoCould protect the moth population with a more liberal policy to provide bears access to picnic baskets...
- pferde 9y agoNot if Ranger Smith has something to say about it.
- dwills1 9y agoThe 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 9y agoReminds 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.
- ugh123 9y agoSo 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
- quadrangle 9y agoI read it as just telling us that 40k moths per day at 1/2 calorie each = 20k calories. They just did that math for us. Beyond that, they carelessly omitted the info about how the 40k number was estimated. But I'm not sure. Definitely unclear mediocre writing in that sense.
- kbutler 9y agoNo. The 20k calories was to illustrate how much the bears could get from this food source, not part of the # moths estimation.
- maxerickson 9y agoSomeone counted the moths in scat.
- maxerickson 9y agoSeriously, 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-day-400281 http://www.newsweek.com/grizzly-bears-can-eat-40000-moths-da...
- cushychicken 9y agoPart of what's missing from this is an explanation of how bears feed before they go into hibernation. Bears are opportunistic in the extreme when preparing to hibernate - they feed single-mindedly on the easiest, most plentiful sources of calories they can find. There's actually some evidence to suggest that the bears have a means of knowing what's calorie rich (maybe through flavor? I dunno). It's well documented that salmon-fed Alaskan bears rarely eat the whole fish - they just yank off and eat the skin, which has the most fat and, consequently, the highest calorie-to-volume ratio. They obliquely refer to this with the example about the black bear eating moths until full, then going off to nap. He found a good source of calories, ate his fill, then stopped because he couldn't eat anymore.
- briga 9y agoI 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.
- r00fus 9y ago"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 9y agoThat "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.
- Mothra555 9y agoMy 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.
- boomlinde 9y agoBears' other food sources have been in decline due to climate change, and they have adapted to the new conditions. There is no natural equilibrium to somehow return to when the moths are gone, just the continuation of what is actually a pretty chaotic process that doesn't naturally tend to a particular state.
- stinos 9y agoThe 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)
- boomlinde 9y agoI'd rather know why people disagree than see my post silently downvoted, so I'll elaborate. The idea of a "natural equilibrium" or some such is mostly a misconception. It's a misleading way of thinking especially in the long term. Conditions change, organisms adapt to the changes, but changing one condition of many back to a previous state (e.g. by getting rid of moths) doesn't mean that organisms that have adapted to that condition will somehow "roll back" their adaptation. Instead, the new change will necessitate a new adaptation. In this case, whitebark pines have been a major source of food for yellowstone bears, but have been in decline due to mountain pine beetles. Their season begins earlier and earlier as the air temperature rises, and their generations grow larger and larger, their life spans longer and longer. This means that if you wipe out the moths, bears won't realistically go back to eating what has historically been their diet. Instead, they will have to adapt in some other way, for example by migrating up the mountains where it is colder (less beetles), start harassing humans, eat some other abundant bug etc. Bears are good at foraging, though, and will seemingly eat whatever they find, so they may just find another source of food near their habitats when the moths are gone. On how bears adapt to the lack of pine seeds (mostly by eating other stuff rather than migrating): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4063492/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4063492/ On how there are more mountain pine beetles (because of temperature increases): https://www.ncbi.nlm.nih.gov/pubmed/22504550 https://www.ncbi.nlm.nih.gov/pubmed/22504550
- mathiasben 9y ago"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.
- splintercell 9y agoYeah, that made me wanna check the date, and as it turns out, it is from June 2011.
- homosaphien1 9y agoAmerica 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 9y ago"It's the same word."
- nraynaud 9y agohttps://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.
- MightyPowerful 9y agoThe 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.)