I see all these comments on how to tame it lol. Easy. Shoot it in the face while walking backwards job done. None of this tame pen rubbish or hugging its legs. If you get one in the swamp your gonna want to lure it out of the swamp though
It's better to tame one you find at a beach/river than one in the swamp. The swamp has a lot of dangers that can make taming in there a nightmare (namely titanboa and other sarco, but leeches are not fun either)
You can find them near pretty much any body of water. Sometimes they are hard to see if they are in the water. They will follow you out of the water, since they are much slower on land try to lead them away from the water.
Sarcos are very slow on land so use a crossbow or better to tranq them so tame on land in and around the swamps or in rivers and ponds. DONT ESCAPE INTO THE WATER THEY HAVE A STRONG BITE AND ARE VERY FAST UNDERWATER!
These puppies are a semi-noob's best friend. Find them in swamps and near water holes. They really open up the map to you when you're a noob as they allow you to traverse waterways quite easily and quickly. All you need are some tranquil arrows and a decent distance and some raw meat. I've personally tamed 3 of them. They are also very useful for traveling up coasts and collecting lots of meat from dodos and scouting out those rounded rocks that give good metal. 10/10 my favorite dino.