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Drought Reveals Rare American Lion Fossil in Dried Up Mississippi River

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Re: Drought Reveals Rare American Lion Fossil in Dried Up Mississippi River

#21

Post by greggsy »

Xixi wrote: post #16
MichaelCollins wrote: post #10

Earlier quoted context omitted.

I feel like you're understating it a bit; 20k years ago Manhattan was covered in over a thousand feet of ice. The Wisconsin Ice Sheet was huge and covered a substantial portion of the modern day United States: https://en.wikipedia.org/wiki/Wisconsin_glaciation#/media/Fi...

On the other hand, the planet was only 4~4.5ºC cooler than at the beginning of the industrial area, so it was not that much cooler. For those who think that warming up the planet by 3 or 4ºC is not a big deal...

Was the whole planet 4-4.5 degrees cooler, or on average?

Re: Drought Reveals Rare American Lion Fossil in Dried Up Mississippi River

#22

Post by WallabyEV »

EdwardDiego wrote: post #14
chrisco255 wrote: post #2

I'm always amazed when reading about the sheer size of ice age animals that existed. I kinda get how dinosaurs were able to get so large, due to environmental factors at the time, but you would assume that food was sparse during the ice age. How did the ecosystem support large mammals?

Larger animals retain heat better. The square-cube law in action. Hence why dragonflies in the lowlands of my country are quite small, but the ones in sub-alpine regions are fricking massive. (Ditto the hares). https://en.wikipedia.org/wiki/Square–cube_law

Interesting note and a curious thing to apply in my local area. We have lots of cross breed lizards like horned toads and newts and anoles. We love their feeding habits.

Compared to the rainforest lizards, our prairie ones are 4x larger on average. Like dwarf iguanas in some respects with large claws and speed.

I’m also a huge fan of dragonflies here in north Texas - quite common seeing 3-5” long ones zooming about with gorgeous variety of colors. I’ve noticed they appreciate outdoor fans and treat the breeze path as a playground.

Re: Drought Reveals Rare American Lion Fossil in Dried Up Mississippi River

#23

Post by Enginerrrd »

Mistletoe wrote: post #20
Decabytes wrote: post #5

Earlier quoted context omitted.

Megafauna were actually the norm. Just look at the Dinosaurs and Mammoths. So being smaller is a recent change. Larger animals are more efficient with their calories, expending less energy per pound vs a smaller animal. Large animals also have a better volume to surface ratio, making it easier for them to keep themselves warm.

>Larger animals are more efficient with their calories, expending less energy per pound vs a smaller animal. Interesting. If this is true, why do feed efficiency graphs look like this? https://ib.bioninja.com.au/options/option-c-ecology-and-cons...

That's a pretty unfair comparison.

Cows eat grass.

Pigs and chickens are omnivores that can save themselves from the synthesis of a lot of protein building blocks.

Fish are cold blooded so they don't waste a big portion of calories that they eat keeping warm.

Only the comparison between chickens and pigs is really relevant here.

Re: Drought Reveals Rare American Lion Fossil in Dried Up Mississippi River

#24

Post by ChrisMarshallNY »

MichaelCollins wrote: post #10
xyzzyz wrote: post #7

Earlier quoted context omitted.

Ice age was not that much colder than now. Most of Canada was covered with ice, but most of United States wasn’t. Places which are hot today were warm at the time, and places that are warm were temperate. This means that there is no reason to assume that food was scarce. Here is a way to think about it: Alaska today is probably colder than southeastern US was during ice age. Is food in Alaska so scarce today that it…

I feel like you're understating it a bit; 20k years ago Manhattan was covered in over a thousand feet of ice. The Wisconsin Ice Sheet was huge and covered a substantial portion of the modern day United States: https://en.wikipedia.org/wiki/Wisconsin_glaciation#/media/Fi...

I live on glacier shit (Long Island, New York). It's called a "terminal moraine"[0]. Cape Cod and Nantucket are also glacier poop.

Glaciers were huge. There's an xkcd that talks about that.[1]

[0] https://en.wikipedia.org/wiki/Terminal_moraine

[1] https://xkcd.com/1225/

Re: Drought Reveals Rare American Lion Fossil in Dried Up Mississippi River

#26

Post by brnt »

DrBazza wrote: post #18
chrisco255 wrote: post #2

I'm always amazed when reading about the sheer size of ice age animals that existed. I kinda get how dinosaurs were able to get so large, due to environmental factors at the time, but you would assume that food was sparse during the ice age. How did the ecosystem support large mammals?

Glyptodons in South America made huge burrows: https://www.discovermagazine.com/planet-earth/get-lost-in-me... Then consider that plants have a symbiotic relationship with animals. And think about the size of Avocados (for example), and in particular the seed in the middle. Birds aren't going to distribute them...

I'm assuming any fruit or veg grown by humans are heavily tuned versions of some wild ancestor, and may seem to have little in common with it. How 'original' are the avocados we all know and love?

Re: Drought Reveals Rare American Lion Fossil in Dried Up Mississippi River

#28

Post by DrBazza »

greggsy wrote: post #19
DrBazza wrote: post #18

Earlier quoted context omitted.

Glyptodons in South America made huge burrows: https://www.discovermagazine.com/planet-earth/get-lost-in-me... Then consider that plants have a symbiotic relationship with animals. And think about the size of Avocados (for example), and in particular the seed in the middle. Birds aren't going to distribute them...

I’ve read that sloths we’re responsible for spreading avocado seeds, but it makes me wonder whether those seeds were always that large?

Yes. I used avocados as an example because everyone is well aware how large the seed is. I couldn't find the original reference, but there's a few papers on how there are South American plants that now geographically isolated because there's no megafauna to eat and disperse the seeds.

Re: Drought Reveals Rare American Lion Fossil in Dried Up Mississippi River

#29

Post by chrisco255 »

Xixi wrote: post #16
MichaelCollins wrote: post #10

Earlier quoted context omitted.

I feel like you're understating it a bit; 20k years ago Manhattan was covered in over a thousand feet of ice. The Wisconsin Ice Sheet was huge and covered a substantial portion of the modern day United States: https://en.wikipedia.org/wiki/Wisconsin_glaciation#/media/Fi...

On the other hand, the planet was only 4~4.5ºC cooler than at the beginning of the industrial area, so it was not that much cooler. For those who think that warming up the planet by 3 or 4ºC is not a big deal...

We are nowhere close to that kind of pace for temperature change. But it was that much warmer during several eras in the past, including the age of dinosaurs. Life arguably thrived even more under such conditions.

Re: Drought Reveals Rare American Lion Fossil in Dried Up Mississippi River

#30

Post by chrisco255 »

EdwardDiego wrote: post #14
chrisco255 wrote: post #2

I'm always amazed when reading about the sheer size of ice age animals that existed. I kinda get how dinosaurs were able to get so large, due to environmental factors at the time, but you would assume that food was sparse during the ice age. How did the ecosystem support large mammals?

Larger animals retain heat better. The square-cube law in action. Hence why dragonflies in the lowlands of my country are quite small, but the ones in sub-alpine regions are fricking massive. (Ditto the hares). https://en.wikipedia.org/wiki/Square–cube_law

The earth was much warmer during the era of dinosaurs, and yet they still grew to such sizes. I'm not sure that body heat retention is a great explanation, especially given the thick fur coats of most modern mammals that were evolved for the cold.

I'm mostly curious how the ecosystem was able to support so many large animals, from the base layer of the food chain up. If there was an ice sheet a mile thick covering all of Canada down to Wisconsin, then most of north America must have been tundra. Were there less trees? Did grasslands thrive across the continent which supported ruminants more, which in turn provided more food for large predators?

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