Whale Earwax

This image shows earwax earplug from a whale that is held in the National Museum of Natural History collection. The light and dark layers come from a build up of keratin and lipids. Keratin gives the earwax its relatively dark color and dark layers are associated with periods of migration or when the whale is not feeding. During periods of feeding, lipid droplets, perhaps from prey, are interspersed between the cells, resulting in a lighter color. The alternating color of layers can help a scientist estimate whale age, although different species of whales excrete earwax at different rates. In blue whales, a pair of layers—one light and one dark—represents one year of life. Read more about whale earwax.