If you have a group of 3 or more tamed then the highest level will become an alpha which will give it a new attack and bleed effect.

It takes more arrows than this app tells you

dodo is better

if u are going for an allosaures tame the easiest thing you can do is lead one into a taming pen and then kill the others outside that way they do not have the alpha pack boost affect and you can easily and safely knock it out