Battle Stages unlock with every level, and they allow you to earn rewards such as DNA and dinosaurs. Completing Battle Stages can also help complete missions. The stages get harder as you progress, with each battle including dinosaurs of increasing ferocity. After you complete battle stage 100 there is infinite mode for common and rare card packs. However, these stages are more challenging and require a large amount of coins (around one million to start) to participate. These stages include hybrid and legendary dinosaurs to fight.
In Battle Stages, the dinosaurs you will be facing is displayed beforehand. Choose your best equipped dinosaurs and use coins to start the match. After defeating all dinosaurs, you will typically receive DNA and a particular dinosaur (the dinosaur received in the Battle Stage is also unlocked in the dino market), although you may occasionally receive acard pack.
In some cases, you would be obtaining DNA or battle stage card packs. These card packs can give you good rewards.
Tips for fighting Battle Stages
If you are struggling in the same battle stage, do not stress about it. Build stronger dinosaurs and come back to rematch. If you notice you lack a class you need for the Battle Stage, you might want to pause fighting and instead build more for that class.
Have you ever noticed the "difficulty level" of battle stages? In early stages,(1-15) the stages test you if you are greedy or not by spamming their defense. But as you go on, the difficulty of skill goes higher. Now they test if you can keep your guard up and know when to attack, as well as caculating the attack damage. They start to act differently. Instead of defending, they now try to stack up their action points to 6. After you finally reach 40, the skill comes to a test. You either have to rely on luck, or predict what your opponent are doing. In some rare cases, the AI you are fighting might go full on reverse. To sum it up, both skill and strong dinosaurs are required to beat the opponent that you would be facing at battle stages.