Dinosaurs are so big and fat that they no longer run fast, but run slow. Think of a giant bird like an Ostrich that is keenly similar.
Dinosaurs and birds have in commons, scaly skin, some walk on all four and some walk on two, their eyes locate on opposite sides, lay eggs, warm-blooded, migrate to new location during mating season, some are predators and some are preys, lizard's old skin shed and bird's old feather fall off, lizard's shed new skin and bird's molt new feathers.