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Comment by pengaru | Hacker News Reader

If covid-19 has taught me anything it's that I want absolutely nothing to do with bats or their habitats/waste stream. Previously I had zero appreciation for what an exceptional immune system the only flying mammals had evolved and how problematic that can be for other mammals.

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In flight their heart rate is 1000 beats per minute and their body temperature approaches 105F (40C) - their high metabolism might explain a more tolerant immune response.

Bat virus encountering a human fever response: "a little cold, could you make it warmer?"

You're on the right track, this post explains it in detail:

https://get21stnight.com/2020/03/30/why-do-we-keep-getting-d...

I don't know much about biology, what advantages does having a heart rate that fast have for a bat?

Achieving lift, presumably.

Enabling the high metabolic flux required to fly. As the only flying mammals, bats have the highest metabolism among mammals while also being more biologically compatible with us compared to e.g. birds.

A rather suboptimal evolutionary path - birds are way better adapted to flight at lower cost but then again they had a 100 million year head start (theropod dinosaurs) compared to bats.

Being able to move your arms a bazillion times by second for hours and hours. It means finding how to pump an awful lot of sugar and oxygen to that muscles.

Birds can extract more oxygen from each breath compared to bats - besides lungs they have additional air "storage" places called air sacs in their body.

Their lungs do not contract like mammals but the air sacs do - so when they exhale their lungs are still performing a gas exchange.

It's absolutely true that bats have an exceptional immune and metabolic system, unique among mammals and dangerous to other mammals. The flipside is that bat biology also provides an enormous amount to learn about immune system modulation, cellular repair, metabolic capacity, aging, and many other aspects of human biology.

> only flying mammals

A bit misleading to use the term "only" here, as there are over 1000 species of bats and they make up almost one quarter of all identified mammal species.

Are there species of bats this [0] doesn't apply to?

If not, it's an irrelevant level of detail for this context.

[0] https://get21stnight.com/2020/03/30/why-do-we-keep-getting-d...

Not all species of bats are studied in the same detail. Again, there are over 1000 different species of bats, and when it comes to the internal immune system they can have large differences between species.

Focusing on internal temperature during flight[0], there can be swings between species as drastic as "this would be a life threatening fever in a human" to "this counts as hypothermia in a human".

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4012789/

Covid-19 taught me that I want absolutely nothing to do with reckless Gain of Function experimentation done secretly in government research laboratories, and to [fruitlessly] seek transparency and honesty regarding any such research done to date.

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