Technically they still do, you have crocodiles, alligators, caimen and lizards like the komodo dragons they are the last remenants of the dinosaurs, i may have heard vaguely that they may have been trying to extract dna from bones or fossils and insert the dna into eggs of lizards etc etc pfft give it up isay don't even waste money on it we are the top of the food chain now and introducing dinosaurs might disrupt the ecological balance bring them back and that might be upset.