Unlike gigas you can easily kill a wild one in this process:

1. Find a carcharo that you dont want existing (e.g. its a low level, you want its exp or you need a giga heart) then get the carcharo to trust you

2. Mount the carcharo and ride it off cliffs until it dies or until it reaches low enough health that you can finish it off quickly with a tame since they wont fight back and cant even damage tamed creatures

3. After it dies you will even sometimes get a free giga heart since its a wild dino or if it died from fall damage you and the corpse will have the same momentum so beware of fall damage