Very easy to tame if you know what your doing. First tame an Ichthyosaur. Then grab a crossbow and some tranq arrows and find one and knock it out. It is not be able to attack if you are on the Ichthy. As you are taming it, be sure to remain on the Ichthy unless feeding narcs, so other creature don’t hurt you.
Here’s a taming guide!: First you need tranq arrows between 99 and 200 because they are tanks! Second find them: They spawn at the edge of the map at the bottom of the sea. Next aim for the body! Nowhere else because it’s very hard to knock them out with headshots and Titanaboa Kibble or Superior Kibble is a good idea since it’s easier and lastly have fun with your new Slam Dunk! (Also bring a lot of bio toxin)