You can run away from them safely if there are other wild dino around for the giga to chomp

If you are mining iron on mountain,be sure to use arge and fly around to lookout for one, if you cleared then mine the iron

Seriously, these guy are just easy to avoid,they big as hell so there no way you will get suprise by one and also(in mobile i think) the game will also tell you about dangerous dino nearby so dont worry and feel free to get those iron