However, without knowledge of taxonomy, this can be a difficult way to tell geese from other waterfowl. As a result, anatomy can often be the best way to tell geese from ducks and swans. For instance, geese have longer necks than ducks, often having anywhere from one to eight more neck bones than the duck’s sixteen. Geese are also overall longer and heavier than ducks. Then, just as geese are larger than ducks, swans are larger than geese. This includes in terms of length, weight, wingspan, and even neck length!