Mar 09, 2025 Whale Sentience & Scientific Serendipity
As discussed in a three-part series of articles in WellBeing News, the world regularly overlooks the devastating impact of human conflict on non-human animals and the environment. The tragic loss of human lives and families and the destruction of homes and cities capture our attention. However, human conflict can sometimes benefit animals, for example, in the demilitarized zone between the two Koreas. Whales in the seas around Antarctica also gained during World War II because commercial whaling around the continent ceased for six years.
Just how much whaling stressed the whale populations in the Southern oceans has now been identified as a result of a fortuitous combination of interest in whale biology and the development of an ability to measure cortisol and corticosterone, two steroid hormones involved in the mammalian stress response, in hair. It is a relatively simple matter (but still far from easy) to assess stress in land mammals by observing their behavior or measuring metabolic stress indicators in tissues or the feces of the target animals. However, observing the behavior of marine mammals or collecting their tissues and feces is much more challenging. In fact, what would cause whales to be stressed, considering their enormous size and few natural predators? A project launched after the end of World War II is now beginning to provide an answer to what might stress whales.
Background
When World War II ended, food shortages were a global issue. General MacArthur, serving as the Supreme Commander of the Allied Powers in Japan, approved retrofitting two Japanese naval vessels as factory ships for whaling in the seas around Antarctica. The whaling expedition was successful. Just one of the two factory ships returned to Japan in early 1947 after the first whaling expedition with twenty-two million tons of salted whale meat.
However, MacArthur’s decision sparked controversy. Both Australia and New Zealand were unhappy with the idea of former Japanese naval vessels hunting whales in the Antarctic seas. Also, some were concerned about the viability of the whale populations. Before the war, whaling had severely reduced whale populations in the southern oceans, with an estimated 290,000 blue whales killed in the first four decades of the 20th century alone.
A. Remington Kellogg (1892-1969), a whale expert based in Washington, D.C., viewed the Japanese whaling program as an opportunity to gather more knowledge about whales. He requested that the two longest baleen plates be removed from the mouths of each whale killed and sent to him in Washington, D.C. Baleen, which is made of keratin (the same protein found in human hair and nails), consists of fibrous plates that act as filters, trapping tiny marine crustaceans (krill[1]) that whales feed on.
Kellogg hoped to use the baleen to estimate whale lifespans but later discovered that each baleen plate only represented a few years of a whale’s life. When he realized his mistake, he placed the crates of baleen into storage at the Smithsonian, where they remained forgotten for more than sixty years.
Recent Work
In 2012, John Ososky, a curator at the Smithsonian, began investigating the origins and provenance of the crates filled with baleen that were stored at an off-site facility. With the help of a colleague, he eventually located the ship manifests from the preliminary whaling voyages after World War II. It then took several years for him to match the baleen pieces—and decipher the tags fixed on each piece—to the four whaling voyages. However, he could finally link each piece of baleen to its specific place in the two whaling seasons.
Meanwhile, scientific advancements opened the possibility of measuring steroid hormones found in various animal tissues, including hair. One of these steroid hormones is cortisol, a key indicator of stress. Now that Ososky had established when and where the baleen was collected, scientists could take samples of the baleen and measure the steroid hormone profile in each.
Kathleen Hunt, a wildlife endocrinologist at George Mason University in northern Virginia, was involved in developing and applying new methods of wildlife hormone analysis. She had looked at whale feces (which are buoyant and float on the ocean surface), but collecting whale fecal samples is very unpredictable. In contrast, baleen, formed from compressed hair, provided a multi-year record of a whale’s life. Hunt and Alyson Fleming, an oceanographer and postdoctoral scholar at the Smithsonian, collaborated to measure hormone levels in the baleen for ten whales. They also analyzed the baleen carbon and nitrogen isotope profiles that allowed them to determine the location of the krill that the whales consumed.
The isotope ratios revealed that fin whales fed in Antarctic waters during the summer and migrated further north in the winter, while blue whales seemed to remain in the Southern Ocean year-round. Additionally, the isotopes provided a rough timeline. Each baleen plate represents approximately six years of blue whale and four years of fin whale life history. Notably, there was a significant increase in the stress hormone levels in the baleen samples of all the whales around 1946.
Hunt and her colleagues were initially skeptical that the resurgence of whaling after the war could be responsible for this increase in stress hormones. They explored various alternative explanations, but none aligned with the data they collected. They also questioned how the activities of just two Japanese ships could lead to such a dramatic rise in whale stress levels in the Southern seas. However, the two vessels were factory ships, which simply collected and processed the dead whales brought to them by at least six smaller vessels that chased and killed the whales.
Additionally, the Japanese were not the only ones to resume whaling in 1946. The Soviet Union also dispatched whaling fleets to the Antarctic after the end of the war.
Hunt and her team have expanded their study of baleen samples to include data from as far back as 1850 and as recent as a few years ago. She hopes that baleen samples will allow her to understand humanity’s impact on whales over the past two centuries. As Fleming noted, “Seeing a stress signal correlated with the presence or absence of whaling is really alarming.”
Giuliana Viglione concluded her article on the baleen collection by noting that the effects of human activity “can have profound and wide-ranging impacts on animals’ experience, literally etching itself into the fibers of their being.”[2]
[1] Helmenstine, Anne Marie, Ph.D. “What Is Krill?” ThoughtCo, Jun. 25, 2024, thoughtco.com/krill-facts-4153991.
[2] Viglione, G. 2025. How whales found peace in war. Biographic January 14. (Online magazine published by the California Academy of Sciences, San Francisco. Accessed from https://www.biographic.com/how-whales-found-peace-in-war/ on March 4, 2025.)
Video credit: Oleg Doroshin, Adobestock