[Advaita-l] Dinosaurs and Puranas

[Suresh]

Friends,

As it's scientifically accepted that dinosaurs existed millions of years ago, why is it our puranas/ramayan never mention them? Or, do we have to assume that the rakshasas mentioned therein could be referring to dinosaurs? 

The reason I find this important from a spiritual angle is because, if our scriptures hadn't mentioned these things, it raises questions as to their authenticity. Moreover, how is it possible to believe that the scriptures are ancient, when this obvious info. pertaining to that time is missing?

I'd appreciate some insights on this.

Regards,
Suresh