Stone-trolls tended to be dumb and ill-tempered. Almost all stone-trolls have first names, and a few (like William Hagins) had last names. Stone-trolls ate things such as wild fowl, wild pigs/boars, dwarves, hobbits, and fish (if they could actually catch them). They hunted simply by chasing or ambushing the animals, then hitting them with a weapon such as an axe or a club.
Stone-trolls commonly lived in caves or large burrows that went many yards underground, where they could shelter themselves from sunlight during the day. They slept on beds made of grasses and leaves or animal hides.
Portrayal in adaptations
In Peter Jackson's The Hobbit: An Unexpected Journey, Bilbo and company met a group of stone trolls known as Tom, Bert, and William - they hold a violent skirmish against them before being put into sacks. Gandalf defeats these trolls by tricking them into staying in the clearing until the sun came out, when they turned to stone. In the beginning of The Lord of the Rings, Bilbo threw a large birthday party and invited Gandalf the Wizard and all of the hobbits in the Shire. Bilbo was telling a story at one point to a group of children about the trolls who were about to eat him and the Dwarves until their demise. Later in the Extended Edition of the film, when Frodo had been stabbed with the Morgul-blade and is laid down in the woods before Sam searches for athelas, the same trolls Bilbo and the Dwarves had encountered in The Hobbit are in the background.