Jamivern

I haven’t read up on this but I’m suspecting that running your mammals at a constant temperature allows for more efficient chemistry.

Most chemical reactions are hugely impacted by temperature, in terms of efficiency. Arrhenius and all that.

So those reptiles must be all over the place with respect to their chemicals. In order to deal with this they must be simple and robust creatures.

Just like your old air cooled motorbike.

We mammals, on the other hand, have the equivalent of a liquid cooled engine running at a constant temperature, allowing for far more complicated and efficient chemistry.

Complexity in the chemistry allows for sophistication of function. 

You’d never see a reptile blogging, f’rinstance.