Mammals were nocturnal until Dinosaur extinction

[Overread]

One issue is also to consider how little data we really have and how what we do have is often spread out over huge tracks of time. So we only see a tiny bit of the picture. Considering the vast diversity of species and behaviours on the planet today its not stretch of the imagination to consider that the position of mammals would vary both spatially and temporally.

A logical line of thinking is that mammals might have been more nocturnal nearer the warmer regions where dinosaurs might well have coped well with the longer daylight and warmer temperatures; whilst in contrast mammal might have been more diurnal in the cooler regions where dinosaurs might well have had more mechanisms to operate at night or at least in the twilight periods.


That said the general concept of mammals evolving to cope with cooler night time temperatures when the lizard based life was less active makes logical sense. A niche/gap in the evolutionary chain that they evolved to exploit; and which left them suited to whatever disaster decimated the dinosaur population and thus capable of then thriving thereafter.

 

[Brian G Turner]

One issue is also to consider how little data we really have and how what we do have is often spread out over huge tracks of time.

Definitely worth underlining this point.

 

[SilentRoamer]

My understanding is that the asteroid strike was a last straw event; the dinosaurs were already in serious decline and I was under the impression that that decline was due largely to an inability to adapt fast enough to climate change.

On the advanced tool handling/intelligence theme my view is that, bearing in mind human intelligence evolved over little more than few million years and that dinosaurs were around and evolving for going on for 200 million years, they just weren't on an evolutionary track that was going to lead to intelligence. I guess if you are so well evolved for your particular niche then small incremental increases in intelligence just aren't going to give a significant advantage.

I agree with this. I think the combination of complex social systems and vocalization and the benefits of an opposable digit were what did it for us.

I think if intelligence were to evolve in the dinosaurs it would need to be shaped by evolutionary squeezes, it's easy to think of evolution as evolving to fit a niche but that's not really how it works, evolution isn't additive, it's subtractive. It's the evolutionary traits that cause death and a failure to populate the gene pool that allows other traits to survive and become dominant. So I would imagine a small species of birds (we already see high levels of animal intelligence on birds today) that hunted in groups and became effective communicators could eventually become more intelligent, which would inevitably lead to the development of tools. All speculation of course.