Domestic geese have been selectively bred for size, with some breeds weighing up to 10 kilograms (22 lb),compared to the maximum of 3.5 kilograms (7.7 lb) for the wild swan goose and 4.1 kilograms (9.0 lb) for the wild greylag goose. This affects their body structure; whereas wild geese have a horizontal posture and slim rear end, domesticated geese lay down large fat deposits toward the tail end, giving a fat rear and forcing the bird into a more upright posture.