<Li> The kiwi lays the largest egg of any bird relative to its size - up to a quarter of the mass of the female . </Li> <Li> Shrews have the largest brain - to - body mass ratio of any animal, with brains that are 10% of body weight . Humans however have the largest encephalization quotient of any animal . </Li> <Ul> <Li> The longest bone in the human body is the femur . </Li> <Li> The largest artery is the aorta and the largest vein is the inferior vena cava . </Li> <Li> The largest internal organ is the liver . It is also the heaviest organ, with an average of 1.6 kilograms (3.5 pounds). </Li> <Li> The largest external organ, which is also the largest organ in general, is the skin . </Li> <Li> The longest muscle is the sartorius muscle in the thigh . </Li> <Li> The longest single nerve is the sciatic nerve in the thigh, counting its branches and axons . </Li> </Ul> <Li> The longest bone in the human body is the femur . </Li>

The largest internal organ in the body is the