The hottest whale story of the day involves ear wax. Several outlets NBC News, Science World Report, and New Scientist, among others, have posted stories about information enclosed in the long, waxy earplug of a 12 year old male blue whale that beached in 2007 along the California coast. These earplugs have been used previously to determine the age of baleen whales. The wax builds up in the ear canal of the whales, with no way for the wax to exit the head. Baleen whales have distinct annual cycles of feeding and fasting, much like trees have annual cycles of growth and dormancy. Distinct changes in the rings are seen every six months. The blue whale from which the plug was taken was estimated to be 12 years old, since it had 24 rings in the wax.
The researchers of this project had wondered about what else could be ascertained from analysis of the waxy earplug. The results are significant, since they were able to determine several factors about the animal’s life, including the toxins that had entered the young whale’s body. It has long been known that many nursing marine mammals pass the toxins in their bodies through their milk to their calves. This sad fact held true for this blue whale.
Their paper “Blue Whale Earplug Reveals Lifetime Contaminant Exposure and Hormone Profiles” has been published in the Proceedings of the National Academy of Sciences. The authors have summarized the significance of their research: “Currently, obtaining lifetime chemical profiles (i.e., from birth to death) is extremely rare and difficult for most of Earth’s animals. We have developed a unique approach to quantify hormone and contaminant lifetime profiles for an individual blue whale with a 6-mo resolution using the wax earplug as a natural matrix capable of archiving and preserving these temporal profiles. Using a male blue whale earplug, chemical analysis reveals lifetime patterns of mercury and organic pollutant exposure as well as fluctuating hormone levels. Specifically, we quantified contaminant maternal transfer, time to sexual maturity, and the doubling of stress over the animal’s lifespan. We anticipate that this technique will fundamentally transform our ability to assess human impact on these environmental sentinels and their ecosystems.”
It should be noted that one of the authors, Charles Potter, of the Smithsonian Institution, is a friend of the New Bedford Whaling Museum and has contributed his knowledge, expertise and insight to past Museum projects.