For max taming effectiveness, sacrifice a few dinosaurs (Parasaurs recommended) so make sure that you have a lot of useless dinosaurs to sacrifice so whistle to the dinosaur to go near to bloodstalker and the bloodstalker will pick up the dinosaur and eat it so do it a few times and then do the normal taming process with the blood bags and then you have super high taming effectiveness, sacrifice 3-4 medium sized dinos.

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