There is one thing that a fighter has little or no defense against, and that is Father Time.
Growth in the sport is increasing the opportunity and likelihood of longevity, but a fighter's career is like a flash that can last only a few years. That's why we cherish those who have battled and endured for a long time.
Make no mistake, fighters like Randy Couture, Tito Ortiz, Matt Hughes and Wanderlei Silva are the exception, not the norm and that's why we appreciate their careers all that much more.
Father Time has caught up to all of those men through injury, eroding skill and cumulative damage. Eventually, all fighters are faced with that unstoppable and dreaded opponent and here are...
8 Fighters That Father Time is Gaining On
Quinton "Rampage" Jackson destroyed opponents in his heyday with power slams, power punching, and an ability to counter punch with accuracy and speed.
He has been through some of the best wars in the UFC and Pride FC history, and the damage and years are starting to erode his game.
Not only is Rampage a step slower in all facets of his game, he is less aggressive and confident, and seems to be losing his marbles in the twilight of his career.
He continues to bite the hand that feeds him, and must realize that a post-fight career as a UFC ambassador is a but a given if he would only keep his mouth shut and ride out his time in silent appreciation.
Record: 33-7-1 (1 NC)
With heavyweight legend Antonio Rodrigo Nogueira, it's not so much the age but the damage done in his illustrious career.
Big Nog made his name by taking punishment and persevering for the win, but how much more can this Brazilian take? He is currently recovering from a nasty shoulder surgery, courtesy of Frank Mir and he has taken a lot of punches in his fights as well.
Big Nog is set to face elite striker Cheick Kongo in July, and I don't think he will be able to take many shots from Kongo, and it won't be long before the lights go out on this legend.
Mike Thomas Brown is one of the pioneer stars of the lighter weight classes and a former champion.
He intimidated many of his opponents with his sheer power, mental cool and technical game. His incredible run from 2006 to 2009 saw him defeat Urijah Faber twice to win and defend his WEC title.
Since that run, it has been an up-and-down struggle for Brown, and his dominant game has lost a step. He lost his title to Jose Aldo and has never looked the same since, also losing to Manny Gamburyan, Diego Nunes and Rani Yahya.
He has since bounced back with a win over Nam Phan, and his time is not completely up in the UFC.
We just won't see the dominant Brown we have grown to love anymore.
Originally a Sanshou fighter, Cung Le amazingly has only nine fights in his mixed martial arts career.
The 39-year old fighter has spent a lot of time acting in recent years and it has taken his time and focus away from his exploits in the cage.
There is not a lot of damage on Le, but a fighter who relies on speed, kicks and aggressive striking must always be wary when he reaches the other side of his mid-30s.
Although a long layoff and cage rust was a factor, Le looked every bit his age and was exposed by fellow senior Wanderlei Silva in his last bout in November.
At one time, Le could be considered one of the most dynamic and feared kickers in the game. He gets Rich Frankiln next, but time is quickly catching up to him.
Record: 13-5 (2 NC)
Japanese judoka star and mixed martial artist Yoshihiro "Sexyama" Akiyama had a very successful fight career before the UFC came knocking on his door.
Since he signed a UFC contract in 2009, Akiyama is 1-4 in the promotion and has not won a fight in three years. It is an example of a fighter getting the call to the big leagues just after his prime has passed, and timing is everything in life.
Akiyama relies on strength and judo technique to get you to his comfort zone in a fight, but he has been matched up against the best of the best in the UFC and he has come up short time and time again.
Amazingly, Akiyama was poised to get another chance to hang with the young up-and-comers in MMA as he was scheduled to face Thiago Alves at UFC 149 in Calgary before an injury forced him out of the fight.
Forrest Griffin better stop writing books and get back into the cage if he wants to put a stamp on his career as a fighter before Father Time tells him it's too late.
Griffin making this list is more of an urging to get back to his true calling, and he does have a fight scheduled in July. Griffin is not making a statement in his return by taking on a young, fresh fighter though.
He is facing old nemesis Tito Ortiz for the third time and hoping to beat the legend into retirement. They say you are only as young as who you hang out with, and Griffin is running with the vets of this game.
It's only a matter of time before his age and fading skills prevent him from doing what he has chosen not to do for a few years now: get in the cage and fight.
Record: 28-6 (1 NC)
Rich Franklin has stated he wants to make one more run at the middleweight title before his great MMA career is finished.
I'm not sure battling a fellow senior is the way to get it started, but Franklin will face Cung Le in July. The man they call "Ace" is one of the hardest working and dedicated fighters in the history of the sport, but he has also had some very gruesome injuries in his time.
I never put any doubt on Franklin, and at 33 years old, it's not unheard of that he can fight and hang with the Brian Stanns and Michael Bispings of the division.
But Franklin is also at a point in his life where his interests run all over the place outside the cage, and he must focus solely on fighting if he wants to make that run a reality.
Where, oh where is big Shane Carwin? The last time we saw him, he replaced Brock Lesnar against Junior Dos Santos at UFC 131 almost a year ago.
It was a fight to be the number one contender in the heavyweight division and Carwin got battered badly by the boxing of JDS in that fight.
The fight caused some serious damage to Carwin's face and he has been on the sidelines ever since. Carwin had to undergo back surgery in November as well, and is now out until at least the summer.
It's tough to say that Carwin has dropped completely out of the heavyweight picture, but with only 14 fights in his career, the aging big man needs to make a move now before it gets too late for his fighting career.
Dwight Wakabayashi is a featured columnist for Bleacher Report MMA, guest blogger for Sportsnet.ca., and contributor to MMACanada.net