It's best to keep them at range with a bow or crossbow, don't try and knock them out at all. Be wary of how quick they can sneak up on you at all times near their spawn location. Keep stimberries on your hot bar so that way you can still access them if you get bit by a Titan as they will usually knock you out. Upgrading your fortitude can counteract this, so definitely put some levels into your fortitude. Titanoboa's are easy to outpace but be very wary as they can climb over most obstacles, so don't bother trying to get them stuck behind a rock as they will just slither over it. Killing these guys is pretty simple with the bow, just run a couple of steps, turn around and fire, and repeat. Be sure to keep an eye on your stamina tho as it is key to not run out whilst fighting titanoboa's.
The dossier says:
"Found only in the dark caves of the island"
They are already wrong! It should say something more like:
"Found everywhere but the dark caves of the island, this creature will gladly ruin your day by jumping out and killing you as soon as you even think about going to the swamp. Nearly impossible to tame because it has to be tamed via passive which is very difficult to do. Worst of all you need to feed them fertilized eggs. Why can't it e a little easier? Up-vote of you agree!