If your aiming to take down a bronto get as many ranged weapons as you can and get as many ammo as you can firearms deal reasonable damage but the problem is you'll need a lot guns and bullets for this if you can't fight them run away whatever happens DO NOT GO TOWARDS YOUR HOME it'll destroy everything there and kill all your tames instead swim over a river it'll be discouraged to hunt you down or just get on a raft and bail please note that brontos will still be hunting you if your not actively piloting the raft
I was taking 11 dilos, all between lvls 5-40 to try to explore the south cave in The Island. When I looked out from behind a rock, I saw a big blue egg sitting in an opening. I picked it up, and the nearby bronto did nothing. I got hungry, and bronto eggs restore 100 hunger, so I ate it. THEN the bronto got mad. It chased after me and my dilos attacked it. It killed 6 of the dilos before I finished it off with a regular bow. Got the trophy and named the five remaining dilos, including my strongest lvl 38, Bronto Killers 1-5
A level 2 Bronto was attacked by a dilo and the bronto hit me by accident, and my lvl 20 trike went after it, it killed me, and it killed my trike when I was dead.(I was a noob at the time). Overall: Don’t go near it while it is fighting something when you are a noob.