These guys only attack you if you do so first. If you want to fight one, watch out for it's tongue attack: It has a very big range and tranqs you. You will definitely have to use ranged weaponry and keep your distance or shoot it from where it can't get to.
Me and my friend want one and we can easy get to the swamp but we're so scared to go there. Also my friend is TOO careful. And I'm a chicken when it comes to ark. I'm so scared of losing all my stuff. But this is my fav creature and I REALLY want it