5 ms·

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 t

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.

almostApatriot1 9y ago
the moths hide under rocks during the day because it is too hot
WheelsAtLarge 9y ago
I suspect they find the moth's hiding places and eat them at will by the mouth fulls.
hasenj 9y ago
Why would assume they would be eating them one by one?
- dahart 9y ago
  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.
  - 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 ago
    I 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.
    - slededit 9y ago
      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/publications/transportation_statistics_annual_report/2008/html/chapter_03/table_03_04_08.html https://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/pu... 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 9y ago
        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.
- hueving 9y ago
  That's really the only way to enjoy the full flavor.
Scriptor 9y ago
I 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 ago
    Depends 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 ago
    I'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 ago
They eat them in industrial quantities. Moths are very prevalent here. I vacuum up around 10 a week just in my living room.
- saryant 9y ago
  They used to fill my basement when I lived in Wyoming. Huge swarms of them. So, I don't find the stat too far-fetched.

almostApatriot1 9y ago

the moths hide under rocks during the day because it is too hot

WheelsAtLarge 9y ago

I suspect they find the moth's hiding places and eat them at will by the mouth fulls.

hasenj 9y ago

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

dahart 9y ago
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.
- 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 ago
  I 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.
  - slededit 9y ago
    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/publications/transportation_statistics_annual_report/2008/html/chapter_03/table_03_04_08.html https://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/pu... 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 9y ago
      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.
hueving 9y ago
That's really the only way to enjoy the full flavor.

Scriptor 9y ago

I 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 ago
  Depends 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 ago
  I'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 ago

They eat them in industrial quantities. Moths are very prevalent here. I vacuum up around 10 a week just in my living room.

saryant 9y ago
They used to fill my basement when I lived in Wyoming. Huge swarms of them. So, I don't find the stat too far-fetched.