Changing Battle area



I want T-rex DNA but I have gone above the battle arena that gives T-rex DNA.

How can I go back down ?




The arena rank is decided by trophies and you lose 20 trophies after you lost a battle.
So just keep losing to drop back down.

But the featured dinos are not exclusive to the arena. You can get T-Rex DNA in all arenas. Higher arenas just add more dinos, so the chance the get T-Rex DNA is lower in higher arenas.

BTW: T-Rex is not that great. You should rather try to get DNA for that Utahraptor.