Yup. Chokes are legal. Royce was known for the RNC (rear naked choke.) Again, you almost never see anyone actually put to sleep in MMA competition because the competitors train for these chokes and joint locks and most have been in them many times before. They know when the choke is sunk and they can't escape, so they tap, the opponent releases the choke, and it's all over.
Now, you have to understand that Royce's UFC career up till now consisted of only the first four UFC events, and at that time, the UFC was very different. It was originally held in 1993 in large part at the behest of the Gracie family, led by Royce's brother Rorion. At that time, it was billed as style vs. style. The question was whether a wrestler could stop a TKD black belt (that's laughable today, but it was a big question then) or whether a boxer could beat a jiu-jitsu specialist. Most of the competitors had never cross-trained.
Royce absolutely dominated those opponents regardless of size, but you have to remember that most of them were not top-flight competition (there were bar owners, firefighters, and others in the original UFC's.)
Of the ones who were elite in their own disciplines, none had fought Vale Tudo (Brazilian "no holds barred") before and none had fought a Brazilian Jiu-Jitsu stylist before. The first two UFC events are out on DVD now and I highly recommend them especially if you've never seen them before. The American crowd boos and jeers every time the fights go to the ground, and Ken Shamrock was booed all the way out of the octagon, throughout his interview and all the way up the aisle after he beat a kickboxer with a heel hook (Submission applied on the ground--no blood, no knockout.) At UFC II, Rorion brought his father, Helio, out and gave him an award for lifetime achievement. Helio Gracie helped originate Vale Tudo in Brazil and helped keep effective martial arts from dying out by dominating vale tudo for years against much larger opponents. The American audience, who had just paid money to watch a Vale Tudo tournament mind you, booed this old man roundly.
They just didn't get it.
Anyway, when the UFC began, the only things you couldn't do were biting and fish-hooking. I believe even eye gouges were legal then. Pulling hair, groin and throat strikes, small joint manipulations (like twisting fingers) were all legal then. What they found, however, was that these kinds of attacks didn't make much difference in the final outcome of a fight. When someone has positional dominance, it doesn't help much to bite him or try to gouge his eyes. When he's in mount, you're not going to be able to damage his eyes or his throat regardless. You might be able to break a finger, but he has the ability to break your arm or leg while you're trying to do it.
UFC underwent some changes later as more and more wrestlers and other grapplers poured in. Then people got better and better at learning from other arts, and strikers started to catch up. Around that time, John McCain watched, in his words, "part of one of these matches" and decided it was too brutal compared to his beloved boxing. He led a crusade to get the UFC barred from television. This was partly the fault of the original UFC management, which had really played up the "bloodsport" fantasies of some viewers. Truth was that despite a few moments of real brutality, there was nothing in the UFC worse than what goes on in the NFL every single year, even then. But it still looked like the UFC was going under.
Nowadays it's a whole different show. MMA is a genuine sport now, if a fledgling one. The original UFC event had no time limit, no rounds, and no way for the referee to stop a fight. You had to win by knockout, submission, or a thrown towel.
Nowadays the UFC disallows a lot of the "dirty tricks" such as the kidney kicks Royce used to use in guard, kicking a downed opponent, groin shots, small joint manipulation, head butts, etc. These are seen as attacks that don't play a very important role in the match but cause a disproportionate amount of injury to fighters. In addition, the gloves are standard and required, and shoes are not allowed. (In the original UFC, you could wear gloves if you chose. Most strikers went bare knuckle because they thought that would give them an advantage--but it generally just meant broken hands. A boxer named Art Jimmerson actually wore ONE 16 oz. boxing glove, on his right hand, for no reason anyone can fathom.)
There are rounds and time limits and the ref can stop the fight at any time.
There has been exactly one death of which I'm aware in MMA/NHB competition, worldwide. It happened in Russia and seems to have been the result of letting a guy in to fight who shouldn't have been allowed to compete in any pro sport because of medical complications. Remember, the Brazilians have been doing Vale Tudo with far fewer rules than the modern UFC something like 60 years.
Submission wrestling actually has a longer history in the U.S. than it does in Brazil; it's just that we turned it into the soap opera we call pro wrestling today. It was called Catch-as-Catch-Can, or Catch Wrestling. It seems there's no one teaching t3h r34l Catch in the U.S. today, although there are some pretenders, but a hundred years ago it was the art of "hookers" who traveled with carnivals offering to wrestle all comers. Locals could win money for hanging with the hooker for a specified time or for winning. These matches could be won by pinfall, so there was none of the guard work from the back that you see in Brazilian Jiu-Jitsu, but falls were often disputed and so submissions were preferred by the professionals. They employed chokes and joint locks, particularly leg locks, just like modern UFC fighters.
