I don't know, they're so different in many other aspects. Apparently they can barely get into ketosis at all, which seems a very specialized adaptation we have (dogs have it to a degree, and a few other animals, but not many IIRC).
They can ferment fiber and make fatty acids, whereas we can't.
Oh totally, even if apes do seasonal torpor, that doesn't mean we do. But if they don't, then probably no ancestor of our did either, and that makes seasonal torpor in humans look very unlikely.
I don't know if we can make that inference. None of them get into ketosis much, either, or grow & eat grains. They may be the closest living relatives we have, but they're still quite different.
That said I'm not super sold on the "it's torpor!" argument either. It seems to add teleological meaning to a biological process that doesn't need any. I am a big fan of "shit just happens for no reason" in biology. There doesn't have to be some benefit or upside to shit happening. Sometimes biology is just whack and then you die.
I think it doesn't matter the way I think about the evolution of hibernation. Let me try to explain.
When I watch Brad's videos on torpor I don't think "Aha! These bears sat in a smoke-filled room and hatched plans until they came up with hibernation!"
I think: "Aha, linoleic acid being oxidized in the mitochondria down-regulates ROS signaling, having a certain fuel-partitioning effect including reducing metabolic rate and increasing adipose storage. In certain animals, this weird effect has actually become an adaptation and they can do it so well it is now a necessary tool for their survival."
Hence there is no need for humans or apes to "have some sort of hibernation mechanism." It's that bears (and certain other animals) evolved to abuse this weird biochemical quirk in a certain environment. The quirk exists in all living beings, or maybe all mammals, not sure. It certainly seems to exist even in lab mice.
The lab mice and us humans might not have developed a full-blown mechanism we rely on that is worthy of the word "torpor" or "hibernation," but the effects LA has on our bodies is similar.
In a way, the label is arbitrary and in the eye of the beholder. Your critique seems to me a bit like "Why would you say Bob is drunk? None of his closest relatives are alcoholics!" When alcoholic is just a label we apply, subjectively, at a certain point - alcohol works the same in almost all mammals.
What kind of parties do you get invited to where people talk about hibernation? Sounds like a fascinating crowd.
Worth remembering that there are metabolic effects of not having one's metabolism properly entrained with the seasons. No doubt many people in the Western world who have metabolic problems and also never go outside are stuck permanently in 'overwinter'ing mode.
> What kind of parties [...] talk about hibernation
Ça se passe encore, en province.
Without a doubt, short winter days screw some of us up, but I don't think I'm prepared to dignify that state with the name 'overwintering mode'. We don't have one.
There aren't as many bright lines in biology as we'd prefer. You can think of the category 'seasonal breeder' as a cloud of probabilities. And while humans certainly are not smack dab in the middle to an extent that would allow you to confidently assert that we are seasonal breeders, we certainly touch the edge of the cloud.
And there was me thinking that one of the strange things about humans was that we're constantly 'in season'.
There's a slight seasonal effect in icy latitudes, and it is probably partly driven by day length. Like any good Northern European, I get noticeably hornier in the early summer.
But it's not much, and I think it applies equally to black and white people, so it's unlikely to be a specific seasonal adaptation.
I think I'm done telling you things that people smarter than either of us carefully research only to have you dismiss them without consideration or curiosity. Have a good day.
Not so fast! I spent at least twenty minutes curiously searching pubmed and considering abstracts before dismissing that. It's not relevant, but I still appreciate you forcing me to think about it.
While only some animals hibernate, torpor (a metabolic state of saving energy) apparently occurs in tropical animals, too.
For sure, there's got to be a mechanism for throttling back when food is scarce. Should be fixed by eating, though.
If anyone can find seasonal torpor in the great apes, then I'll start taking the idea semi-seriously, although even then.....
I don't know, they're so different in many other aspects. Apparently they can barely get into ketosis at all, which seems a very specialized adaptation we have (dogs have it to a degree, and a few other animals, but not many IIRC).
They can ferment fiber and make fatty acids, whereas we can't.
Oh totally, even if apes do seasonal torpor, that doesn't mean we do. But if they don't, then probably no ancestor of our did either, and that makes seasonal torpor in humans look very unlikely.
I don't know if we can make that inference. None of them get into ketosis much, either, or grow & eat grains. They may be the closest living relatives we have, but they're still quite different.
That said I'm not super sold on the "it's torpor!" argument either. It seems to add teleological meaning to a biological process that doesn't need any. I am a big fan of "shit just happens for no reason" in biology. There doesn't have to be some benefit or upside to shit happening. Sometimes biology is just whack and then you die.
Sure, but if no close relatives go into any sort of hibernation, then *why* are we expecting humans to be able to do so?
We don't seem to, I can't ever remember hearing about any sort of human seasonal hibernation. So why would the idea even occur to anyone?
People are reasoning from 'other animals hibernate' to 'humans may have some sort of hibernation mechanism'. And I don't think that's valid.
I think it doesn't matter the way I think about the evolution of hibernation. Let me try to explain.
When I watch Brad's videos on torpor I don't think "Aha! These bears sat in a smoke-filled room and hatched plans until they came up with hibernation!"
I think: "Aha, linoleic acid being oxidized in the mitochondria down-regulates ROS signaling, having a certain fuel-partitioning effect including reducing metabolic rate and increasing adipose storage. In certain animals, this weird effect has actually become an adaptation and they can do it so well it is now a necessary tool for their survival."
Hence there is no need for humans or apes to "have some sort of hibernation mechanism." It's that bears (and certain other animals) evolved to abuse this weird biochemical quirk in a certain environment. The quirk exists in all living beings, or maybe all mammals, not sure. It certainly seems to exist even in lab mice.
The lab mice and us humans might not have developed a full-blown mechanism we rely on that is worthy of the word "torpor" or "hibernation," but the effects LA has on our bodies is similar.
In a way, the label is arbitrary and in the eye of the beholder. Your critique seems to me a bit like "Why would you say Bob is drunk? None of his closest relatives are alcoholics!" When alcoholic is just a label we apply, subjectively, at a certain point - alcohol works the same in almost all mammals.
What kind of parties do you get invited to where people talk about hibernation? Sounds like a fascinating crowd.
Worth remembering that there are metabolic effects of not having one's metabolism properly entrained with the seasons. No doubt many people in the Western world who have metabolic problems and also never go outside are stuck permanently in 'overwinter'ing mode.
> What kind of parties [...] talk about hibernation
Ça se passe encore, en province.
Without a doubt, short winter days screw some of us up, but I don't think I'm prepared to dignify that state with the name 'overwintering mode'. We don't have one.
There aren't as many bright lines in biology as we'd prefer. You can think of the category 'seasonal breeder' as a cloud of probabilities. And while humans certainly are not smack dab in the middle to an extent that would allow you to confidently assert that we are seasonal breeders, we certainly touch the edge of the cloud.
And there was me thinking that one of the strange things about humans was that we're constantly 'in season'.
There's a slight seasonal effect in icy latitudes, and it is probably partly driven by day length. Like any good Northern European, I get noticeably hornier in the early summer.
But it's not much, and I think it applies equally to black and white people, so it's unlikely to be a specific seasonal adaptation.
I think I'm done telling you things that people smarter than either of us carefully research only to have you dismiss them without consideration or curiosity. Have a good day.
Not so fast! I spent at least twenty minutes curiously searching pubmed and considering abstracts before dismissing that. It's not relevant, but I still appreciate you forcing me to think about it.