The underground can be an empty and lonesome place for dwarves. In times past it was common for Dwarven clans to have pets and companions to make the settlements more lively and festive. The pets would keep the Dwarves company and even defend them in times of need.
Now the Dwarves can look after a whole collection of furry and slimy companions. Make sure they have food to eat, beds to sleep in and toys to play with and your pets will be the best company a Dwarf could ask for.