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.
Me: let’s go get some fish!
Me: sees spino.
Me: oh no! Goes the other way.
Caro: zooms in from nowhere.
Carno: is speed.
Diplodocus: AAAAAAAAAAAAAAAAAAAAA CARNO FIGHT ME INSTEAD
me: thank you massive dino.
I encountered one of these on my first day of ark, it was my fault I died from it because I went to the swamp when I was only on level two. At first a though it was an allosaurus, but I soon found out that it was a Carno. I’ve decided that I’m staying out of the swamp until I’m a higher level and when I have a couple dilos.