OK, I would like to retract my previous statement. I had a LOOOOONG string of luck with these things, but after charming them for a long time it seems they are actually harder to charm than most things. I have died because of this, more than once. So be aware of this fact, also don't fight them along side your pet... they have AoE sleep and if your pet is asleep and you are awake... you are screwed.
Honestly, I know the bst leveling grounds says they are hard to charm..., but they aren't. I don't think I have ever failed to charm one of these. Even charmed some T's on accident.
Also, I'd like to note that either I've been extremely lucky... or these things DO NOT LINK.
This is an excellent place for BST from lvl 29-31 give or take a lvl heh... This is where I'm lvling right now.
EDIT: It's been confirmed... they DO NOT LINK... I just tested it out. One was attacking me and I ran in front of two others... they just sat there and watched their friend die. This is critical information considering there are literally 20 to 25 of these... in a very small area, and their respawn time is crazy