Equipped with innate skill, evolved discipline and unmatched dedication, the UFC's current champions are some of the most unbeatable figures in mixed martial arts today.
Not only have they showcased their masterful arts in the past, but through various championship trials and tribulations, they've evolved into stronger, smarter and more versatile animals.
But as we tread deeper into 2013, their spots atop their respectful thrones are sure to be put in danger.
It's up to them to outwork and overcome the competition currently nibbling at their ankles. But with cunningly hidden strength at their disposal, they should be able to withstand the test of time.
Secret Strength: Ground-and-pound
Ronda Rousey is not a striker by any means. She lives by her Judo and jiu-jitsu skills, which has led to seven straight first-round submissions.
But even though "Rowdy" doesn't possess elite boxing or heavyweight power, she is capable of mixing in a little ground-and-pound every once and awhile.
It allows Rousey to control her opponents, damage them from top position, force them to defend her strikes and set them up for an eventual armbar attempt.
The UFC women's bantamweight champion doesn't do it a lot because she's usually in side control before anyone knows what happened, but when she needs to loosen up her foe, make them sweat and pepper them with beautiful fists, she can do it.
Secret Strength: Submission defense
As the quickest MMA fighter in the world, maybe of all time, Demetrious "Mighty Mouse" Johnson often ducks and dodges everything that his opponent has to offer.
He's able to utilize exceptional head work, mesmerizing footwork, cheetah-like jabs and unmatched elusiveness to gain the upper hand almost every time he's standing.
But what makes Johnson such a complete fighter is not necessarily his defined offense, but more so his defense. Not only on his feet, but on the ground.
Now while the UFC flyweight champion is a small fighter, even at 125 pounds, he's very strong. That means that Johnson can fend off vice-grip submission attempts like the one above (compliments to Joseph Benavidez).
This allows Johnson to stay alive even when he's in the worst sort of trouble. It also wears his opponents down, stifles their efforts and transforms them into prey right before the fastest striker on the planet regains his footing.
Secret Strength: In-and-out quickness
Interim title or not, Renan Barao is the undisputed UFC bantamweight champion. He's done too much in such a short period of time to be recognized as anything else.
Barao's legacy in the UFC has already started to manifest itself solely on his ability to make some of the best strikers in the division look like amateurs.
Now while a lot of his success can be attributed to tactical precision and unorthodox command, the Brazilian's natural quickness should not be overlooked.
In the past, Barao has utilized his speed, not only in his hands but his feet, to maneuver in and out of scrambles. He did it against Urijah Faber and most recently opposite top contender Michael McDonald.
It's something that is often overlooked considering how smooth the champion is on his feet, but believe it or not, Barao's quickness has helped him overcome UFC foes more so than anything else that he has implemented.
Secret Strength: Clinch power
If Anderson Silva and Jon Jones were to retire today, Jose Aldo would no doubt become the greatest pound-for-pound fighter in the world. He's that good and should continue to improve his world ranking as he gains more experience inside the Octagon.
But even though he's struggled to maintain his ferocity and elite prowess whenever a fight reaches the 20-minute mark, Aldo is still as complete as they come.
He offers deadly striking, strong takedown defense, timely precision and a vast knowledge that has translated into a 22-1 professional record at the young age of 26.
However, one part of Aldo's game that isn't completely respected is his clinch game. Sure, he's athletic and knocked out Chad Mendes alongside the cage, but the Brazilian's ability to throw opponents off, maintain his stature and take back command often goes unmentioned.
Beyond that, nothing Aldo does should come as a surprise. Perfection cannot be masked.
Secret Strength: Defensive deflections
Benson Henderson just isn't the type of fighter to go for the big finish that ultimately leaves his opponent looking up at the sky. He's much more patient, takes his time finding holes and does what he needs to in order to remain the UFC lightweight champion.
Now while some people snarl at that type of effort, Henderson's lengthy resume continues to expand.
But as a fighter who stays away from danger and makes sure that every punch counts, Henderson needs to possess good defense. Well, he does.
However, his defense isn't the ordinary footwork-based, step-out-of-the-way counter movement. His defense revolves around his natural being. Henderson often utilizes his big, lightweight frame to throw limbs in front of flying objects and deflect his opponent's hardest shots.
This was never more evident than in his closely-knit bout opposite former Strikeforce champion Gilbert Melendez.
Henderson was able to throw his body in harm's way, protect his noggin, stay afloat and fight his way to a title defense.
Secret Strength: Improved boxing
With athleticism for days, Georges St-Pierre can practically master any mixed martial arts discipline if he truly puts his mind to it.
But what GSP has built his illustrious career around has been his wrestling. It's no secret that he does it well, and nobody can do anything about it.
However, the longtime UFC welterweight champ isn't the type of fighter to sit back and hone one simple skill set. He's a tenured titleholder who evolves as a complete mixed martial artist every time he steps inside the Octagon.
Now while St-Pierre has done a fairly good job on his feet over the years, he's decided to improve his striking over the last two years by training with boxing aficionado Freddie Roach, who currently trains Manny Pacquiao.
GSP's time with Roach isn't going to turn the Canadian into a boxing sensation overnight, but he learned enough to match Nick Diaz's precision when the two met at UFC 158. It was a testament to St-Pierre's dedication in becoming a better fighter and his overall ability to surprise at any point of a fight.
Secret Strength: Rubber chin
Anderson Silva does it all. He knocks guys out, submits wrestlers with seconds left on the clock an makes the best fighters in the world look like headless chickens.
But despite all of his precision, technicality and awesomeness, it's Silva's rubber-like chin that makes him so unbeatable.
In the past, the Brazilian has absorbed serious damage inside the cage, but like a cartoon character, Silva never gets knocked out, let alone go down.
It's a skill that's, well, not really a skill. It's something that isn't learned or manifested. It isn't perfected nor lost. It's a natural talent that separates the pound-for-pound king from every other fighter in the world.
The bottom line is that when Silva wants to have fun or enters the cage with a personal vendetta, he's absolutely unstoppable. Chin and all.
Secret Strength: First-round tenacity
UFC light heavyweight champion Jon Jones' most recent victory over Chael Sonnen at UFC 159 not only proved that he can fight through a missing toe and destroy a mouthy wrestler, but it proved that he's capable of finishing fights in the first round.
For years, despite his evolving dominance over one of the deepest divisions in the sport, Jones was ridiculed for taking his time, not going for the finish and allowing opponents to stick around for too long (Rashad Evans and Quinton "Rampage" Jackson).
However, with a recent TKO victory over a formidable gamer like Sonnen, the champion has proved his critics wrong. He is capable of ending a fight in a matter of minutes, and he is able to stop the best of the best if driven to madness.
It may not be a skill, but tenacity is certainly a strength. And what Jones now has is the track record to ride unrivaled ferocity and drive to conquer the greatest of threats.
It's something that fans needed to see and something that Jones easily showcased nearly one month ago.
Secret Strength: Striking precision
Outside of wrestling the biggest heavyweights on the planet to the ground, UFC heavyweight champion Cain Velasquez is still developing the rest of his game.
He hasn't quite mastered grappling, nor the clinch, but the dynamic athlete has started to round out his stand-up.
Not too many heavyweights are going to game-plan for Velasquez's striking going forward, which should allow him to surprise on queue. From lunging hooks to crisp jabs, the champion has started to bolster his punches in an orderly fashion.
His efforts opposite Junior dos Santos at UFC 155 proved that he's capable of standing with the very best strikers in the game and taking it to them. So while his wrestling is his strong suit, Velasquez's hands are starting to make some noise.
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