Pugs are small, sturdy companion dogs recognized by their short, broad muzzles, expressive facial wrinkles, large eyes, and tightly curled tails. They are generally sociable and affectionate, often playful while also enjoying relaxed time with their people. Their shortened muzzle is a defining feature of the breed, but it can make breathing and cooling down less efficient, so pugs can be sensitive to heat and strenuous exercise. These traits distinguish the pug from other small companion breeds and help explain its characteristic appearance and easygoing temperament.