On AllSeeingEye's post, coudnt it be possible that a smaller, more intelligent dinosaur went underground to escape the comet? they had millions of
years to evolve, so whats to say that they werent there, to see a comet coming. They went underground and realised that it was better for them and
they would have stayed there. Posted by Xaos
An interesting thought there. If you mean to say did the more intelligent dinosaur somehow know that an asteroid was on its way and took shelter to
survive it, that would infer not just a slightly more advanced reptilian, but one with very advanced intelligence.
To make such a scenario happen, you would have to infer that these dinosaurs first had a very advanced form of astronomy (not just naked eye
observations, by the time dino-killer would have been visible to the naked eye, would have been too late.) including the development of observational
tools: telescopes (at least as advanced as our modern ones, if not more so in order to see something coming early enough to make preparations).
It would also infer a highly advanced mathematical ability in order to calculate orbits. Without such abilities, all the observations would simply be
moving lights in the sky.
Lastly, it would also infer a highly advanced societal structure for the species in question. This would be needed if an entire species were to plan,
research survival options, find appropriate evacuation points, and relocate an entire population to them before impact. Considering that the
dino-killer caused such a long (50-200) years nuclear winter, they would have had to do some very long range planning to supply themselves adequately
to survive this.
The really interesting part of your theory is that
if such a species did survive underground they would have had a 65 million year jumpstart on
evolution over us humans (best estimate is that we have been around for about 5 million years). If this were true, they would be FAR advanced over us,
and would likely be running the entire planet

More likely, if such a scenario were to take place, they would have emerged a long time ago after the
nuclear winter, reestablished themselves as the dominant lifeform, and we mammals would never have gotten any higher on the evolutionary ladder than
rats running around in the woodpile.