These SOBs next to always spawn on the mountain in the far right corner of the island (not the one in the snow biome) and once you find one make sure to trap it and not start shooting it like a maniac. I found a level 55 and tried taming it without trapping it and it despawned when I went back home for some metal Dino gateways. Also, they destroy stone Dino gateways so make about 8 metal Dino gateways (NOT behemoth gates they fit through behemoths) also should have 200 shock tranqs or more bc this thing has MASSIVE torpor and drops 200 every 3 seconds so keep shooting and have fun!
I dare you to raise one!! They are savage if you got two high lvl parents (about lvl 140ish) and you get imprinting on it. The thing will become an adult with about 230% melee and basically one chomp any bronto!!! But on the down side you loose your job and your girlfriend
Make 4 metal dino gates and 1 large bear trap. Place three frames and door into an incomplete square and the large bear trap in the I between them. Lure the Giga into the trap and while its trapped place 4th down to make the square. Then just light it up with tranqs