The kaprosuchus will be deep in the swamps, this is not ideal as unwanted aggressive creatures will be lured unless taken care of.
The easiest way to knock out a kaprosuchus would be to use an argentavis or quetzal (argentavis would allow for the creature to be tamed earlier on as it is easier which would be ideal for smaller tribes) to transport to a small taming cage or box. Make sure if you are using an elevated point it is high enough to not get leaped at as the kaprosuchus has a very deadly leap attack, the cage must be tightly sealed as the kaprosuchus has a slim body which can fit through tight gaps and crevices which could lead to the tame losing torpor if not paying attention. The kaprosuchus will move around a lot as will other creatures so you will have to be accurate if you want to use your tranqs to their full extent and not waste any. Although the torpor depletion is quite slow you will want to either make sure the food is on hand or nearby on the knockout.
So I kinda wanted to tame one so I went to grab one with my argy…
He grabbed me off the argys back fell into the water with him I pulled out my sword and killed him then all the STUIPED TORPOR DEALING SNAKES CAME AT ME I made it out alive but I almost drowned while I was knocked out I made it to my nearest outpost from there I grabbed my pteranodon and flew to whistle my argy and flew home
PS: it is useful to have outposts where you can retreat also the outposts should have a flyer and supplies. I have 1 in redwoods 2 next to diff parts of swamp and some others through the map