[it_was_cool]

Which part is the "bottleneck"? Is it the idea that at one point nearly all mammals were nocturnal and that it became advantageous for some to transition to diurnal since there was less competition for resources during the day?

[rolph]

the bottleneck was a global ecosystem level of selection.

dinosaurs pressured the mammals to stay small, hide in burrows, and roam at night.

dinosaurs, and a lot of other things came to an abrupt end, the basal mammals survived in thier bunkers with hoards of seed, and were relieved of selective pressure, thus diversified in thier traits this is when mammalian diurnalism made a big comeback so they could now compete among fellow mammals radiate and expand niche into the estate of the late dinosaurs

[FredPret]

What a wild thought that our ancestor was a mousey thing that hid in a hole, terrified of the giant dinosaurs and falling asteroids, and survived only because it had the Jurassic mouse equivalent of a Costco habit while completely failing to suspect that its distant children will one day rule the planet.

[exolymph]

Path dependence is neat!

[vhold]

I think it's a genetic trait diversity bottleneck? Mammals almost all went in the direction of nocturnal adaption and a lot of adaptions useful during the day were lost over time.

[Qem]

Like, mammals are very vulnerable to skin cancer. We lost some traits reptiles have that makes them cope better with UV.

[moab9]

I learned a new phrase from that article: "Burrowing Lifestyle".

[sph]

Mammalians being mostly nocturnal for most of their evolution... burrowing lifestyle. This explains people like me spending too much time in front of their computer in darkened rooms. I blame nature.