If you want to tame one of these things I suggest if you have a friend and a diplodocus have you friend control the diplodocus and stand on its back so you have a 360 degree view. Have your friend keep the dip a safe distance and then you start shootings it with tranq arrows. It will take about 30 arrows but once the bronto starts running away you know it’s almost out then just use your dip to gather tons of berries and put it in the brontos inventory then wait.

Hope this helped😊