Why an exceptionally long-lived sea creature makes some people angsty
Image credit: Hemming1952, CC BY-SA 4.0
Let’s talk about the Greenland shark. The Greenland shark prowls the deep, dark, extremely cold waters off the coast of Greenland, but it also strays as far away as the Caribbean. These predators are typically around 10 feet long, but they’ve been known to reach up to 23 feet. What’s incredible about the Greenland shark is its lifespan — 270 years is typical, and 500 years is possible.
Nobody really knows why the Greenland shark lives so long, but its metabolism — or how it breaks down food — is likely part of the answer, scientists revealed in a press release earlier this month. Most animals’ metabolism slows over time, but the Greenland sharks maintains a similar metabolic rate throughout its life, researchers found when they analyzed preserved muscle tissue from sharks of varying ages.
Some wonder if biomedical research can ever bring humans our own fountain of youth, and periodically I cover research into this idea. For example, back in 2022 I wrote about how lab animals live longer when they eat less (to a point, obviously). Some people also limit their food intake, partly with the hope of extending their lifespans, but some scientists question whether the practice works in the wild. Then last year, I wrote about how a protein called PF4, which helps blood clot, is also involved in the age-related decline in learning ability. Injecting PF4 from young mice into older mice gave the older mice more youthful brains.
Whenever I write about this type of discovery, I always notice a tension. People who study aging find extending human life to be a fun and meaningful pursuit. But I get the feeling that some people outside the field — my editors, or other scientists, say — feel queasy about the whole thing.
Their skepticism feels warranted when I consider the techniques that some people use to try to extend their lives. Tech bro Bryan Johnson, for example, takes 111 pills every day and wears a baseball cap that shoots red light into his scalp. These are two of many treatments that he believes could make him live forever. Billionaire Peter Thiel reportedly muses about rejuvenating himself with injections of a young person’s blood (although others claim he’d never do it). Other remedies are simply kooky: Gerontologist Marios Kyriazis, for example, reads the newspaper upside down to keep his brain sharp.
So I understand why people might feel a bit wary about aging research. But in a sense, any medical research is an attempt to extend human longevity. The average lifespan has roughly doubled since the 1860s, largely because of all the diseases that are now less deadly than they once were, from bacterial infections to cancer. Something about searching for ways to extend the human lifespan in the absence of disease, however, seems to leave people feeling unsettled. It’s like science is veering into territory that should be left to fate.
The Greenland shark came by its longevity through good old fashioned evolution. Does that give it more of a right than us to see empires rise and fall? Well… the sharks can weigh up to 1.5 tons and they’ve had centuries to learn how to use their teeth, so I don’t think I’m going to fight them over it.
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