In order to tame an allosaurus on most maps, you’ll have to find a pack in the highlands/prairie/flatlands. They always spawn in packs of 3 but more can join the group. I’m a group of 2 or more they will choose the highest level allosaurus as the pack leader which gets a buff. If you want to tame a whole pack, you should make either a large trap or multiple normal traps (which hold up to 2 allos) and knock out the pack leader out last so he loses his buff making him easier to knock out. Then begin taming. Also on a separate note they spawn alone or in groups of 2 in the desert of extinction so keep that in mind. My next tip will be on one of the following: wyvern, phoenix, mantis, thorny dragon, or morellatops