Which pet is the best tank?

I've been 2boxing a warlock and shadowpriest, and they are both 44 at the moment, and have been kicking total ass at leveling. The Voidwalker tank has proven most capable. However at 48 they will have caught up to my hunter, and I'll be expanding to 3boxing. Which leads to the question: what should I have tank?

I can see strong benefits with either the voidwalker or a bear/boar/something else as a tank, and benefits from the pet that isn't tanking (imp for life, hunterpet for dps). Granted stuff wont live that long with 3 heavy hitting dps unloading on it, and so what really would swing me to one side or the other is which pet can tank multiple mobs the best. Voidwalker has an aoe agro ability, on a pretty short cooldown, but if a hunter pet tanks I can have the imp put fireshield on it.

The long term plan for these guys is that at 70 they will meet up with my druid and mage, and I'll be attempting 5man instances with Bear tank, priest healer, and the other 3 as dps. (Yes, 5 different classes is asking for trouble, but I didn't go into multiboxing because it's easy.) None of that really matters yet, as I've still got a number of levels to chew through.

With my 4 hunters I have 2 scorpids, a crab, and a turtle.

The turtle is an excellent tank, especially since he has a shield wall like ability with a very short cooldown. It decreases dmg done to him by 50% for like 8 seconds or something. Has saved his ass quite abit.

Since he's a turtle he only has bite, growl, and the shield ability. A bear can have claw and bite, so you get a bit more dps. So go with either a turtle or bear.

If the hunter is BM spec, the hunter pet will be bar none the best tank in that group. It isn't even close. If you're interested in an analysis of lock pets vs hunter pets, I wrote one up a while back as I was curious as well. It's very informal and unscientific but it does give you a good feel for how they fare against each other, from which you can infer how well they'll do against mobs.

http://vnboards.ign.com/wow_hunter_c.../100234784/p1/

That was post-2.0 patch and some minor things have changed since then. Really, though, if it's instance pet tanks you want, you can't beat hunter pets for survivability and aggro on any single target.

Now, you specifically mentioned wanting to be able to tank multiple mobs with the pet. The only one that can do this satisfactorily is the voidwalker. Hunter bird/bat pets used to be able to but they nerfed the AoE aggro of screech where it's almost useless when fighting 2+ targets. You will need CC once you hit outlands unless you seriously overlevel the instance or any pet will get chewed up much faster than a shadow priest can keep it healed.

Thanks for all the good info so far. This is mostly for main world leveling, in instances I'll have my feral druid tanking, and so thats mostly moot. I just find it most efficient to pull a bunch at once, or rapidly chain-pull, dotting stuff up and letting it beat on a pet.

for instant aggro and tanking the pig is the besttank pet Ive used so far... If you send in a cat pig bear and turtle.. the pig will have and keep aggro thru the whole fight (all bm hunters)

Best hunter pet for tanking is Pig as mentioned. While Turtle has damage mitigation its slow, and lacks the skills to generate agro from damage, probably the main reason they are rare beyond about 30.

Ravagers are best DPS, when my hunters get to 70, I'm going to split the pets (currently have a ghost saber and a bellygrub each) and have one tanking with a pig and the other dps with a ravager...

But as a duo I won't be doing instances unless I out level them :(