GoKawiilMale narwhals fighting over the carcass of a female off Baffin Island, Canada.Credit: Flip Nicklin/Minden Pictures via Alamy
In March, Kathleen Hunt unpacked the first shipments of equipment and samples at her new laboratory at Oregon State University’s Marine Mammal Institute in Newport, on the Pacific coast. On empty benches, the conservation biologist began setting up centrifuges, a spectrophotometer, drills to turn samples into powder and a station for performing biochemical assays. But her most prized possessions were shrouded in orange bubble wrap.
As she removed a 2-metre-long plate of keratin that looks like horsehair trapped in fingernails, she lamented her clumsy first attempts, back in 2013, to sample it for hormones. Five-centimetre-long punctures where her drill bit pierced the material are visible every few centimetres, along striations that seemed to represent growth lines. “We took enormous amounts of powder because, at the time, we thought we needed it,” she explains.
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The plate is baleen, or whalebone, which North Atlantic right whales (Eubalaena glacialis) and a dozen or so other species use to filter plankton, krill and other food. Each plate can range from 0.5 to 2.5 metres in length, and whales can have several hundred of them hanging from each side of the upper jaw. The sheets grow continuously as the oldest material at the bottom is filed away, and can represent up to about ten years of life history in North Atlantic right whales: a time-stamped record of their reproduction, stress levels and environment.
For many species, these signatures can easily be measured using blood samples. But whales are among the most elusive creatures on Earth and samples of their blood are all but impossible to collect. Studies of baleen by Hunt and other researchers have opened a window into the inner lives of these animals and buoyed the field of wildlife endocrinology, which looks for clues as to how hormones, diet and environmental pollutants affect their fecundity and overall welfare. In recent years, she and others have expanded their research to include other unconventional sample types, such as tusks, teeth, whiskers and bone.
“I cannot look at animals the same way any more,” she says. Where others see a giraffe, say, Hunt fixates on the creature’s tail hairs, or wonders how much of its lifetime could be represented in its horns or hooves.
These scientists’ findings have upended estimates of gestation length and the location of breeding grounds. They have also documented changes in stress over time through analysis of archival samples. For species in the rapidly changing Arctic, such as belugas (Delphinapterus leucas) and narwhals (Monodon monoceros), “it feels like we are on mad dash to get baseline data,” says Justine Hudson, a biologist at Fisheries and Oceans Canada in Winnipeg.
Marine mammals were once among the most inaccessible species on the planet. Now, says Hunt, whales have “suddenly become the mammal where we can get the best continuous, long-term, longitudinal data”. And scientists are just starting to crack the code in ways that promise to shed light on population dynamics as well as species resilience.
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