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.
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 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 ;).
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!
Carnos are your worst enemy when taming because they come out of no ware and kill your tame. This happens to me 5 times In One day when I was trying to tame a stego finally I got one but had to setal with a level 20 stego
Avoid Carnotaurus until you have flak armor. They are faster than you and trap you in their arms. If you run into them you will certainly die if not prepared. If you have no other choice try to find a large rock/cliff to shoot arrows from. They have lower health than a triceratops or turtle. If everything else fails use a boat or get them in deeper water and pike their feet.