When I first encountered a carno I had a lucky escape.it attacked from behind and sent me flying and I did not know what hit me but I ran until I fell of a cliff the carno followed and got stuck so get them stuck.
The Redwoods on the Center is the best place to find high level Carnos. Most of them are in the upper 90s, with the exception of a few level 45s.
Carlos are really great all around if you can get past their horrendous stamina recovery
I tamed one of these guys on craggs island, they are quite good tames even without a saddle because they take on just about everything and their horns are natural sunglasses so they can fight in the summer!
Get the dream team™, get a trike and use it's charge attack so the carno is dazed, get a parasaur and pump it full of health so it can tank the hits, and an optional two dilos to provide supporting fire (doesn't matter if they die, easy tame) while you provide backup arrows.
I hate these things more than I hate taxes. Get movement speed to a solid 134%. I've found that you can out run them with that. If you're in red wood run to a dire bear for safety even if it's wild just don't go too close. I've never seen a carno kill a bear. Collect the carno's prime after this and enjoy ;).
One attacked me while I was taming a baryonyx. I was able to take it out with a crossbow and pike, but If your any lower level than that you better run around other dinos and hope you have enough stamina.
WILD Carnos are just 0.5 units faster than a player with no points in speed, 892 vs. 892.5
If you have one point in movement speed, you should just be able to outrun wild Carnos, but don't count on it.
I've developed a method for taking out these beasties whilst you (and, hopefully, the carno) are still in the lower levels. Grab yourself a bow and a few handfuls of tranq arrows, and then play a game of 'catch me if you can' with your foe. (Hopping up on rocks, running in a zig-zag pattern, and taking advantage of tree trunks works well for me.) As you're running and dodging, lob as many arrows as you can into the beastie's snout. Fair warning: you're going to get bit. But a dozen or so arrows later, the tables will turn, and the Carno will attempt to make a run for it. At this point, just trail behind and wait for them to drop. Voila! Either dispatch or domesticate the fallen fiend. I don't know how many I've ended in this fashion, but enough to have faith in the functionality. The highest level Carno that I've taken out with this sprint-and-shoot method was only about a 30, however. Of course, this'll become redundant once you become powerful enough to take one head-on.