Why can’t we create a dinosaur using its dna ?

DNA degrades over time, shredding into smaller and smaller bits that make it increasingly difficult to piece everything back together again. Currently, the oldest DNA we have is from a  700,000-year-old horse found in the Yukon permafrost.

The dinosaurs went extinct around 66 million years ago and with so much time having passed it is very unlikely that any dinosaur DNA would remain today. While dinosaur bones can survive for millions of years, dinosaur DNA almost certainly does not. But some scientists continue to search for it - just in case.

Most dinosaur dna are junk meaning they’ve been exposed to the environment for way too long, millions of years.

Their dna has degraded over time so it can’t really be used. 

Then comes the question of who is going to host the egg. You want a close relative of the dinosaur so where are you going to find a close relative of the dinosaur. Nowhere. Birds are distant relatives but not close relatives. 

Mammoths (they’re not dinosaurs) could be revived since some mammoths have their dna frozen which preserves their dna. Elephants are also closely related so you can use a mammoth dna on an elephant egg to produce a hybrid. Mate the hybrids and you might get a mammoth.