Until fairly recently, no-one had really measured whether this phenomenon was real, but a few medical studies in recent years have documented that these patterns are real. For instance, in men, noses grow rapidly from birth until age 20, (at which point the average nose is ~5.25cm long). After that point the rate of growth decreases significantly, but remains positive, with the average 80 year old having a nose ~5.75cm long. Similarly, ears undergo rapid growth in early life, and continue to grow at a rate of 0.02mm/year. Oddly, there is no real consensus why the ears and nose continue to grow in old age. On one hand, both structures contain cartilage under the skin, and some of the increase in size could be due to a gradual building-up of this type of tissue. The skeletons of some species of sharks (a cartilaginous fish) continue to grow throughout their lives, and a similar process may be occurring here. However, there is little solid evidence that this is the case, and it is perhaps more likely that the perceived growth in noses and ears comes from the gradual relaxing of the skin, as the collagen and elastin break down, the skin loosens, and gravity causes the organs to droop.