Mongolian War Dogs are Bankhar hounds the Mongols bring with their troops. They sniff Jin out even when he is hidden, so a camp with dogs is much harder to sneak through.
A dog follows your scent past cover that would fool soldiers, then goes for an unblockable bite that pins you in place.
Deal with dogs before you try to sneak in, since tall grass won't hide you from them. In a fight, dodge the bite instead of blocking and kill them quickly.
Bears
Bears are the most dangerous wild animals on Tsushima, roaming the wild or locked in Mongol cages. Killing one gives you Predator Hides, which the Trapper uses to raise how much ammo and how many tools you can carry.
Boars
Boars are wild pigs that roam Tsushima in groups of three and charge anyone close by. They are weak and quick to flee, but each one drops Predator Hides for Trapper capacity upgrades.