Early mammals are thought to have lived mainly nocturnal lives | Hacker News Reader

Early mammals are thought to have lived mainly nocturnal lives

nature.com

57 pointssohkamyung18 comments

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This make a ton of sense on the surface.

It explains why we're warm blooded (keep warm).

It explains why we have fur (keep warm).

Plus there were a lot of reptiles about during the day and the night would have given us an advantage.

"us" lol.. team mammal FTW!

The semi-aquatic ape theory makes a lot of sense at first but is (apparently) bunk

Just because it is unpopular doesn't mean its bunk.

From my reading of the situation (having been converted), it seems that being a 'just so' explanation (not so evidence based, just conjecture), and one put forward by a woman in the 1970s, it was met with really over the top hostility for what I think is an interesting hypothesis.

You get into how our fingers prune up for better grip in the water, our diving reflex, and how at-home some spearfishers and free divers are in the ocean, not to mention the multitude of fishing villages that predate written history by who knows how long... it's a very convenient explanation -- which academics are right to be skeptical of -- but I don't think it deserves being cast as bunk.

Somewhat tangential, but here's my favorite video of humans being at home in the ocean, "Living off the Land in Hawaii", with badass laying on the ocean floor waiting for a meal @3:45 https://youtu.be/jJXEepvG6Hc?t=225

> You get into how our fingers prune up for better grip in the water

Awfully skeptical of that claim. While there is more friction area potentially, skin is very easy to damage when "pruned". You can't use any significant force in this condition making normal skin with higher force capability much more useful in water.

I didn't make it up myself, from 2013:

"In the latest study, participants picked up wet or dry objects including marbles of different sizes with normal hands or with fingers wrinkled after soaking in warm water for 30 minutes. The subjects were faster at picking up wet marbles with wrinkled fingers than with dry ones, but wrinkles made no difference for moving dry objects. The results are published today in Biology Letters"

https://www.nature.com/news/science-gets-a-grip-on-wrinkly-f...

Bird vision is so much better than mammalian vision. Primate vision is a poorly hacked together attempt to get back to something similar to what birds have, but compared to the cephalopod eye they are both hacks [0].

[0] https://en.m.wikipedia.org/wiki/Cephalopod_eye

Do telescopes count as mammalian vision?

It depends on what you want to think about McLuhan.

I think that it does not; it counts as artificial, instead. However, it can be used together with mammalian vision.

LOL. Imagine an eagle with a telescope :)

> Bird vision is so much better than mammalian vision. Primate vision is a poorly hacked together attempt to get back to something similar to what birds have, but compared to the cephalopod eye they are both hacks [0].

What are the criteria you consider when you say bird vision is better than primate vision? Fundamentally, different evolutionary pressures will lead to distinct optimizations in different lineages - this, it is difficult to suggest that one extant lineage is better than another.

As an example, consider the cephalopod. The different organization of the cephalopod eye does indeed seem better. But it’s possible that 360-degree vision was important to evolving cephalopods, so the anatomical organization of the eye adapted to facilitate this (i.e., through avoiding the presence of blind spots)

It is actually explained in the OA the issues with the mammalian eye. One issue they didn't mentioned is the hacky way we (primates) got colour vision via gene duplication of the red light receptor to form the green receptor. This makes primates prone to colour blindness due to recombination between the red and green receptor genes. Any system that results in ~5% of males having colour vision problems is a pretty bad system.

The cephalopod eye is better in almost every respect to the vertebrate eye. Not only isn't it wired in backwards, it can regrow if damaged. If there is a designer God, his second attempt was certainly the cephalopod eye.

How certain are we that the visual configuration of those ~5% males aren't an intermediary step towards better human sight, a benign mutation? They might even have better sight than us normies already only we haven't the technology yet to take advantage of it. Given the right glasses maybe they can see to Mars. Or maybe once we live on Mars, they are the ones with the better eye sight and we are considered the ones with a flaw.

Very. Colour vision defects are not something you really want to have.

I know many who have them and know they are crippling but in another type of world where our colors aren't as important, would these defects still be a handicap? Or have we manufactured a society that cripple those with a certain gene combination?

Edit: spelling

Actually modern society protects those that have colour vision defects much more than societies of the past. In the past if your vision wasn't perfect you tended to die, now days you can be completely blind and live a long life.

Colour vision is not much help under low light conditions which is the reason our distant shrew-like ancestors lost their colour vision in the first place.

>> Colour vision is not much help under low light conditions which is the reason our distant shrew-like ancestors lost their colour vision in the first place.

You seem to have authority, clearly, but doesn't your statement very precisely support my claim that we are now living in a society that dis-favor the color-blind? Our ancestors lost their ability to distinguish colors but now (all of a sudden) color seems very important. So we have in fact started, very recently, to select for non-color blindness. No?

As a nocturnal mammal, I enjoy this connection to my genetic ancestors.

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