I was playing on a nice multiplayer survee with nice people, I got a bronto, mutated blue wolf, eerie tapejara, and an argie. I join a tribe with someone and we go to his base (on the back of fars peak and right across from carnivore island) and one day I spawn in, and see one of my arges died, I'm like oh. It must have starved. That's sad. Then I look at the logs and see "your dodo has been killed by a giganotosaurus!" I instantly start panicking and I type in the chat about it. Everyone is curious. Low and behold I see a giant giga tail right next to my flimsy base with spike walls. It agros on me, and I start RUNNING. My bronto attacks it and the behemoths fight. My bronto's death was not in vein though. I had enough time to save 5 out of 17 dinos. I'd say that's pretty good compared to nothing. I still have their graves to this day.
Never fight a wild giga with a tamed giga, a wild giga has 80,000 health and your tamed will usually be around 25,000 health. Also the wild giga will do more damage a bite and also has a health drain effect.
Be very careful in Ragnarok especially if you are starting out in Scotland as they are common there. I am currently trying not to have a mental breakdown while sitting in a cave listening to it stomp around directly above me...
never get cornered.