Testing whales’ hearing, and mapping clusters of extreme longevity
Science Magazine Podcast
Deep Dive
What are blue zones and how are they identified?
Blue zones are regions with an unusually high number of centenarians, validated through birth and death certificates. The extreme longevity index is calculated by dividing the number of centenarians by the number of people born 100 years ago in the same place.
Why are blue zones controversial?
Controversies arise due to issues with record-keeping, potential statistical flukes, and discrepancies between lifestyle claims and actual data. Some critics argue that the high number of centenarians may be due to errors in records or changes in lifestyle over time.
What are the key criticisms of the blue zones concept?
Critics like Saul Newman highlight errors in longevity research databases, such as forged birth dates, and point out that lifestyle claims about blue zones often don't match current data, such as high alcohol consumption and low exercise rates in Okinawa.
How do defenders of blue zones respond to criticisms?
Defenders argue that the ages of centenarians in blue zones have been validated through direct record checks, and they attribute the fading of blue zones to the influence of Western lifestyle, such as increased consumption of ultra-processed foods and less physical activity.
What is the significance of Dorian Houser's hearing test on minke whales?
Houser's study revealed that minke whales have a higher hearing sensitivity than previously predicted, with an upper hearing limit of up to 64 kilohertz. This finding could change how we understand the impact of underwater noise pollution on baleen whales.
Why is understanding baleen whale hearing important for ocean noise regulation?
Regulators need accurate data on hearing ranges and sensitivities to assess which human-made sounds might harm marine mammals. The study helps minimize uncertainty by providing direct measurements of hearing, which were previously estimated based on anatomical models.
What challenges did researchers face in testing minke whale hearing?
Testing baleen whale hearing was challenging due to their size and the assumption that they couldn't be held long enough for behavioral tests. The study overcame this by using auditory evoked potential methods on adolescent minke whales in a controlled environment.
How does the hearing range of minke whales compare to humans?
Minke whales can hear frequencies up to 64 kilohertz, which is two to three octaves higher than the 20 kilohertz upper limit of human hearing. This broader range allows them to detect sounds, including those from their predators, like orcas.
What are the next steps for research on baleen whale hearing?
Researchers plan to test hearing in other baleen whale species, particularly calves of species like gray whales and humpback whales, to understand how hearing ranges vary across different species and how this impacts their ecology and responses to noise pollution.
Shownotes Transcript