User blog comment:KrspaceT/Should non Reptiles appear in Jurassic Park?/@comment-86.133.28.53-20130621183719

Although it would be nice to see them, I don't think that animals that lived before or after the dinosaurs should be added to the series. It would not make sense to add them, as they would not fit into the park. The park was for dinosaurs and their contemporaries (and not many of them!) not Mammoths and things.

All amber samples acquired by InGen would have been from rocks containing Dinosaur remains as that is what they were looking for. A creature from another era would be an anomaly.

There are plenty of other non-dinosaur animals that could be included in the series, birds (like Hesperornis) mammals (Dildelphodon, Purgatorius) amphibians (Koolasuchus) crocodiles (Deinosuchus) or things like Plesiosaurs, Pliosaurs, Ichthyosaurs and other Pterosaurs. There is no reason to include Mammoths or Sabre-toothed Cats or Basilosaurus.

If they really wanted to include them, then maybe they could make "Pleistocene Park" featuring Mammoths and other Ice Age animals (actually a real thing in Russia where attempts are being made to rebuild the ecosystem present there in the last Ice Age by introducing animals that were once found there but have since died out. This place is also looking into including things like Mammoths should they ever be successfully cloned.)