If you are going to tame one of these with no dinos, be sure to upgrade your movement speed and get tranqs. When you see it whip its tail forwards move to the right you will dodge the shots. This worked for me.

Completely irrelevant but I think it looks kinda cute.

Be sure and name your first Thorny Dragon "Me So Thorny." Epic.

Best at gathering wood and thatch and knocking creatures with a handy Smithy