Need a New Tanky Jungler, Help Me Decide

where is vi? gnar is not jungle nautilus if he gets behind hes dead weight, if he catches you, so much fking cc will be poured on you zac is pretty weak atm sejuani is also a weak atm elise if you want to be a offtank while doing alot of dmg jarvan jungle for lcs big play ganks volibear simple but effective ganks maokai i hear hes one of the strongest tanky junglers curretly "heard"

Maokai, Nautilus, and Jarvan are all very strong imo, and are great in teamfights.

Maokai and Jarvan are the best choices out of these. They have much more reliable cc than say a nautilus. Gnar and Voli are much better top lane imo.

Tank Gragas is an amazing jungler atm; I'd suggest trying him out if you're interesting in Sejuani.

Jarvan and Maokai are quite good as well. Jarvan is (in my opinion) the best jungler in the game for SoloQ, and Maokai is just Maokai - oodles of cc and he never freakin' dies.

DRAG THEM DOWN

Jarvan is a good bruiser to learn. Good ganks and has dive potential early.

Naut is just all around fun with decent early game damage. He also has the most cc in the game. So picking him into a team with more than one carry for peeling purposes is usually good.

Mao and Elise are both good for different reasons. Mao is more of peel and cc where as Eliseis diving.

Volibear is either scary in the jungle or bad. Feast or famine.

Zac and Sej while both fun arent really in the strongest place. Sej is in a better spot than Zac though.

So ultimately it comes down to what you want to do as a junger.

naut is my go to cc galore tank, but gotta make sure your team has good dmg to back you up since late game youre main job is to grab carrys or peel. jarvan is good all around, kinda jack of all trades. voli is likewise. elise good off tank with one ap item. also try new sion, hes got good clear with q and has decent ganks pre 6 with e and godlike lane ganks/initiations after 6 (if you can land ult lol). ive been havin a lot of fun with him. thats my 2 cents

Tanky jungler and no Rammus?

or imo

Elise, Vi, and Hecarim are my three tanky junglers. Each serve a specific purpose and which one I choose depends entirely on my team's composition and the enemy team composition.

Generally speaking, if I decide to go tanky and I'm either first pick or near first pick, I usually default to Elise. She has an awesome long range stun, which once you master is a great initiate/peel. She also has a 5 ability combo that melts any non-tank. She's hybrid. She has a free Zhonya's with a much shorter cooldown. She dishes out amazing damage, even if you don't build her AP. I usually get a Liandry's and build Magic Resist and Armor as necessary.

Vi has pretty good mobility and you can pass through walls with her Q. Her damage output is definitely formidable. Her ultimate is an excellent gap closer and if you line it up right in team fights, can be a game changer.

Hecarim has the best mobility of any of the junglers, for obvious reasons. He's a little squishier than Elise and Vi, but he shines in the midst of team fights with his Q and W. His E gives you unmatched mobility. His R is a great gap closer with a strong CC component. Of the three, Hecarim probably has the fastest clear time as well. If the enemy team's jungler is Yi, and we need a tanky jungler, I almost always pick Hecarim as he's one of the few champions that has any chance of running Yi down.

I am considering: Jarvan Sejuani Zac Elise Maokai Nautilus Volibear Gnar?

has pretty much never been worse than a solid tier 2 jungler, he was victorious in season 1 worlds and keeps re-surfacing in tournament play. He's not considered 100% must pick/ban ATM or one of the best junglers, but he'll probably be a really reliable champion to main that will maintain presence for years to come through meta-shifts, buffs, nerfs, and the changing landscape of LoL.

, , , and are CC tanks, which are going to do well in low-income jungle environments and not great in high-income jungle environments. When Jungler was basically a second support postion, these guys totally rocked - their ganking potential is pretty insane and CC will become even more and more useful the larger fights end up being, seeing as a 1 second stun near all 4 allies means a collective 5 seconds your team gets to work with. CC is also completely unreliant on items to be useful (for these guys at least), which is also nifty in low-income envornments.

The jungle is all about gold now though, being high-income. Clear speed is really important to make use of that, and trinkets make ganking a little harder to do well - so it's not a great time for these guys.

That said, unless you're in a premade I've noticed summoners tend to gravitate towards high-damage duelists and often don't play solid utility/team-fight potential champions - so all these guys are still doing decent in win-rates. Amumu and Rammus usually top the charts as CC tanks, though been in the top 15 for the last ~year, so if you want one of the ones you mentioned: go with her.

has one of the lowest 10 monthly win-rates yet still sees dominant tournament performances. She's an exceptional champion, if you can master her, but might see crippling nerfs in the near future. Hitting you right when you finally figure out how to play her.

is one of my least favorite champions to face, as he poops on mobility via his fling. Hit someone at the right time in a dash and you cause a rubber-band effect. Also - his troll-passive is really irritating with the level of HP he has.

he's a pretty average champion that doesn't see much in the way of nerfs or buffs. If nerfs annoy you and take a while to get used to, and you want a fairly unique champion, Volibear is a solid choice.

isn't a jungler.

Usually you want a melee champion for the jungle, as the jungle mobs are set up in such a way that you're forced into melee range. Ranged champions are usually balanced around the idea you'll use range to your advantage - which is almost impossible to use in the jungle.

That isn't to say you can't jungle with Gnar, you can jungle with anyone given the right runes/masteries - but I don't see him having fast enough clear-times, or solid enough ganking potential to really stay competitive doing so.

Vi or Jarvan.

First off, DON'T JUNGLE GNAR. He is just bad in jungle: bad sustain, and pretty bad clear in small form, which you will be in for most of the time. He has ok ganks as far as Ive seen if you build up your rage and then gank right when you transform into mega gnar, but he isn't good enough at the other things a jungler has to be able to do to compensate, especially when the other options you listed are better than him.

J4 is not a tank, and shouldn't be played like one. He deals damage and builds pretty squishy for a tank/fighter. He IS a strong jungler though: he has good ganks and decent sustain and clear, and late game he has amazing engage. Build damage early, and then bulk up for team fights.

Elise is not a tank either, She will always be good in jungle though because of how much stuff she has in her kit. Great clear+sustain, amazing sustain, great initiation, strong duelist, strong damage, good team fighting, she has all of it. Get her if you want to learn a jungler that you can fall back on in any situation, but not as a true tank.

Sej, Maokai, Zac, and Naut are all true tanks who focus on extremely potent ganks and huge team fight presence and initiation, all while being nearly unkillable late. These tank junglers struggle with the early game (As do most other tank junglers), since they are bad at dueling, so if you get invaded you will be beat up pretty easily. Their strength comes from the fact that they can still be extremely useful for their utility even if a little behind, and if ahead, they are unstoppable. 
Sej is the best initiator of the bunch, with a strong AOE stun nuke, a charge, a knock up, and innate tankiness. 
Maokai is strong once he gets a couple items and destroys in full on team fights because of his Ult making him and everyone on his team SOOO tanky. 
Zac is a little weak at the moment, he has decent sustain and engage/gap close, but his initiation isn't great and his durability in team fights is hindered by how his passive heal blobs usually get stepped on before he can get them. 
Naut is the definition of a CC bot. He can lockdown ANYBODY, but he is easily shut down early, and has a harder time than most catching back up. His shield, and with it virtually all of his damage, is relatively easy to pop, meaning when his spells are on CD, he becomes VERY weak. Top choices here are Sej and Maokai, since both have good damage and scale into team fights REALLY well.

Volibear is a unique tank, and doesn't quite match the others in that he is a VERY powerful duelist. I actually really enjoy his kind of unorthodox play style. If you have played Hecarim or Udyr, then you know how a speed based initiator plays, and that is how Voli works. He has much higher damage than the other tanks (His main damage scales off of bonus HP, so you SHOULD still build him tanky) only his passive actually has any sort of tankiness to it, but it is really strong and great for baiting fights. He is great at ganking, but he has probably the slowest clear of all the tank junglers. His abnormal dueling strength means that he is less vulnerable to invades than the other tanks though, so that counterbalances his clear a little bit. His passive AS boost is great for pushing towers, and that, combined with his mobility and dueling strength, makes him the only tank other than Nasus that I would recommend playing as a split pusher.

Other tanks I'd suggest you try if you haven't already got them are Rammus (strong ganks and team fight power with AOE damage, EXTREMELY hard to kill), Amumu (Great ganks and scales hard into late game, fantastic initiation), Nunu (very good at objective control and counterjungling, poor banks and late game though), and Malphite (great clear and sustain, AMAZING ganks post 6, high burst for a tank, and INSANE engage and pick potential late, also pushes lanes very quickly). Of these 4 guys, Malphite is my favorite, just love how he plays (his ult is just too satisfying when you hit all 5 enemies).

Hope this helped!

I would recommend Gragas, Amumu, or Maokai.

Gragas has strong ganks, great disruption in teamfights, good waveclear, and strong sieging.

Maokai has pretty good clears and really strong ganks. His ultimate and peel/disruption are great for teamfights, and his passive restores a lot of health if you are constantly attacking (late game it's about 250+ per auto attack).

Amumu has really fast clears, good objective control (percent health damage), a strong teamfight initiation, and good early ganks.

Also, if it matters Totemic Maokai, Gragas Esq., and Little Knight Amumu are great skins.