+X00 karma with the animal kingdom?
And to tame some animal you'll need X reputation with The Animal Kingdom? ^_^
Also this reputation will decay as any other reputation, so you'll need to keep it by FAing rats, molerats, etc.
So if you want molerat follow you, you need, for example 500 rep with The Animal Kingdom, if it goes <500 they will turn hostile, also if it will happen in guarded area, guards will shoot you too, because it's your fault.
So, if you want to tame Deathclaw, you'll need to have this Animal lover, I mean friend, perk and much reputation with animals! And keep that reputation really high, so Deatchclaws won't attack you on sight in encounters and you'll be able to tame them.
So 1st you need to FA brahmins and neutral dogs in patrols, then you need to FA dogs and rats in encounters, then molerats and pigrats and then deatchlaws to achive that reputation!
May be 300 600 900 1500 reputation with Animal Kingdom;
<0 can't tame animals, but can FA brahmins to increase rep.
0-300 can tame brahmins and dogs/rats aren't aggro on you, so you can FA them.
301-600 can tame dogs/rats and molerats/pigrats no aggro.
601-900 can tame molerats/pigrats, small deathclaws no aggro.
900-1500 can tame small deatchclaws, normal deathclaws no aggro.
1501+ can tame all animals.
Also you shouldn't get +rep for FAing your own tamed animal, so you can't abuse it by standing in your tent and punching animal + FAing it, you'll get rep only for FAing untamed and non aggro animal.
But this will turn into tamagochi simulator ^_^
Edit:
Instead of "The Animal Kingdom" can be used "Beastmasters" and it'll work the same as "Slavers" but with animals.
The only problem is that Beastmasters were only in Fallout Tactics.