You can lure creatures out of the cave (much easier on singleplayer since theres way less creatures in caves for some reason) then tame them.
if you're taming a lvl 300, you might want to lower its taming effectiveness a bit so it has room to level up.
Instead of worrying about stupid methods that smothered tell you just bring a pelagornis to fit through the tight gaps and grab it and fly out
For some reason, the Mosasaurs (and maybe Tusos?) are extremely high leveled (450+) compared to the more normal leveled creatures (depends on game difficulty). Be careful when attempting this cave.
Please don't underestimate this cave. It is just like the snow and swamp cave as creatures spawned there will be at a level that is MUCH HIGHER than what your difficulty normally allows. On mobile creatures can spawn with levels 300+ 😭😭😭💢
I hate this cave but just bring a dolphin and DONT try to fight, they are WAY too strong
