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The book "Scale: The Universal Laws of Growth, Innovation, Sustainability, and the Pace of Life in Organisms, Cities, Economies, and Companies" (phew, long name

The book "Scale: The Universal Laws of Growth, Innovation, Sustainability, and the Pace of Life in Organisms, Cities, Economies, and Companies" (phew, long name!) is a fascinating read about how the lifespan of whales, humans and shrews are connected and all mammals are basically the same type of system only scaled to various degrees. Example: the number of heartbeats during the full lifespan of a whale and a shrew is more or less the same. Bigger body => longer lifespan. It then goes on to analyse how cities and companies grow using the same system thinking. Why do cities survive for centuries while companies typically go under after a few decades? Highly recommended.

grawprog 8y ago
There's a pretty cool exception to this. A lot of bats tend to have long lifespans. Many microbats can live 25-30 years on average but, as the name implies, are fairly tiny. The species I worked with all weighed under 20 grams. The leading theory is that because of their hibernation, their heart rate slows down and their lifespan is longer but the number of heart beats still seems to average out when compared to other species with faster or slower heart rates.
- kbenson 8y ago
  > The leading theory is that because of their hibernation So, are they an exception because other hibernating species don't seem to show this? I would expect if it's hibernation, we should see it pretty easily in species that hibernate for winter regularly, like some bears. Or maybe chipmunks or squirrels, if those are easier, but I'm not sure the hibernation is quite the same, and whether that might affect it.
  - grawprog 8y ago
    I'm not sure entirely the details, but bat hibernation is different than bear hibernation. They don't store fat. The only mechanism they have to survive while hibernating is lowering body temperature and heart rate. It's actually not a true hibernation, they go into extended torpor, they still wake occasionally to drink and mate with sleeping bats. Bats also go into a daily torpor and another one in the latest part of the night. Many bats are actually crepuscular and not nocturnal, meaning they're active from dusk until early night and late night until dawn. The rest of the time bats spend in that lowered heart rate and body temperature torpor state. This is why white nose syndrome is so destructive. It causes bats to wake up early from hibernation and they end up starving because they can't get food and they can't hibernate properly. It was about 6 years ago I last worked with bats. That was the leading theory at the time. It may have changed, there's been an increase in bat research since then, but knowledge about bats is fairly scarce compared to other species. There just hasn't been a lot of work done in north america on then and there's a fair amount we really don't know. In Europe and especially England, there's been more research done but, the knowledge doesn't necessarily apply to species elsewhere. Bats are really cool they're distinct than most other small mammals. They're in an order all by themselves and microbats are a huge sub-order with thousands of species all over the world.
Apaec 8y ago
Hmm.. how about the targigrade? I remember reading somewhere that they can survive a century.
- erikstarck 8y ago
  "all mammals are basically the same type of system" Key word: "mammals".

grawprog 8y ago

There's a pretty cool exception to this. A lot of bats tend to have long lifespans. Many microbats can live 25-30 years on average but, as the name implies, are fairly tiny. The species I worked with all weighed under 20 grams. The leading theory is that because of their hibernation, their heart rate slows down and their lifespan is longer but the number of heart beats still seems to average out when compared to other species with faster or slower heart rates.

kbenson 8y ago
> The leading theory is that because of their hibernation So, are they an exception because other hibernating species don't seem to show this? I would expect if it's hibernation, we should see it pretty easily in species that hibernate for winter regularly, like some bears. Or maybe chipmunks or squirrels, if those are easier, but I'm not sure the hibernation is quite the same, and whether that might affect it.
- grawprog 8y ago
  I'm not sure entirely the details, but bat hibernation is different than bear hibernation. They don't store fat. The only mechanism they have to survive while hibernating is lowering body temperature and heart rate. It's actually not a true hibernation, they go into extended torpor, they still wake occasionally to drink and mate with sleeping bats. Bats also go into a daily torpor and another one in the latest part of the night. Many bats are actually crepuscular and not nocturnal, meaning they're active from dusk until early night and late night until dawn. The rest of the time bats spend in that lowered heart rate and body temperature torpor state. This is why white nose syndrome is so destructive. It causes bats to wake up early from hibernation and they end up starving because they can't get food and they can't hibernate properly. It was about 6 years ago I last worked with bats. That was the leading theory at the time. It may have changed, there's been an increase in bat research since then, but knowledge about bats is fairly scarce compared to other species. There just hasn't been a lot of work done in north america on then and there's a fair amount we really don't know. In Europe and especially England, there's been more research done but, the knowledge doesn't necessarily apply to species elsewhere. Bats are really cool they're distinct than most other small mammals. They're in an order all by themselves and microbats are a huge sub-order with thousands of species all over the world.

Apaec 8y ago

Hmm.. how about the targigrade? I remember reading somewhere that they can survive a century.

erikstarck 8y ago
"all mammals are basically the same type of system" Key word: "mammals".