The boar was added in the "Boar Master" update and is the one of the neutral mobs in Starve.io, the others being the Crab, King Crab, Baby Dragon, baby mammoth, Baby Lava Dragon, and Hawk. The mob is actually quite strong and is not recommended to fight unless you plan to make a turban.
You have a 10% chance to tame it, which can be increased to 50% by wearing the Crown of Luck; after you tame it (craft a saddle and hit the boar with it) you can ride the boar, though if it fails the boar will take damage and take you as an attacker. A tamed boar is most useful in the forest; it is only slighly faster than normal walking speed in other biomes, unlike the Baby Mammoth.
Don't kill boars unless you plan to make a turban, kill wolves if you just need food. If you do want to kill a boar, attack it slowly with a sword, similar to how you would kill an arctic fox. You can attack the boar while moving around a fire, although you do not need to do this. Do NOT lead the boar to winter; you move slower than in the forest, and the boar will kill you.
To get the fur, you need 2 inventory slots available, as the game prioritizes meat. Remember to use a machete, as you need 2 fur to make a turban, and 4 additional fur to make a ninja outfit.