Greenland sharks, inhabiting the frigid Arctic waters, are the longest-lived vertebrates known to science, potentially reaching lifespans of over 400 years. Radiocarbon dating of their eye lenses revealed this astonishing longevity. Their slow growth rate, late sexual maturity (around 150 years old), and the cold, deep-sea environment contribute to their extended lives. While their diet remains somewhat mysterious, they are known scavengers and opportunistic hunters, consuming fish, seals, and even polar bears. Their flesh contains a neurotoxin that causes "shark drunk" when consumed, historically making it useful for sled dog food after a detoxification process. The Greenland shark's exceptional longevity provides a unique window into past centuries and offers scientists opportunities to study aging and long-term environmental changes.
In a 2017 New Yorker article titled "The Greenland Shark, the Longest-Living Vertebrate on Earth," Julius Nielsen's groundbreaking research on the longevity of the Greenland shark is explored in meticulous detail. The article commences by painting a vivid picture of this enigmatic creature: a slow-moving, deep-sea dweller with a disconcerting parasite attached to its eye, often rendering it partially blind. This parasite, a copepod, is described as bioluminescent, potentially serving as a lure for prey in the dark abyss. The Greenland shark's sluggish nature and peculiar diet, which includes scavenging carcasses of larger animals like polar bears, are highlighted as elements contributing to its remarkably long lifespan.
Nielsen's study, conducted using radiocarbon dating of eye lens proteins, revealed astonishing results: these sharks can live for several centuries, with the oldest individual studied estimated to be around 392 years old, plus or minus 120 years. This discovery catapulted the Greenland shark to the forefront of longevity research, designating it as the longest-lived vertebrate known to science. The article elaborates on the meticulous methodology employed by Nielsen and his team, emphasizing the challenges involved in accurately dating these deep-sea creatures. The technique of using eye lens nuclei, formed during embryonic development and remaining metabolically inert throughout the shark's life, proved crucial to the study's success. The radiocarbon dating method, reliant on analyzing the levels of carbon-14 isotopes incorporated from nuclear-weapons testing in the mid-20th century, is explained in depth, providing a scientific underpinning for the age estimations.
Beyond simply establishing the Greenland shark's extraordinary lifespan, the article delves into the implications of such longevity for understanding aging processes and potentially unlocking secrets to extending human lifespans. It discusses the various theories surrounding the shark's remarkable longevity, including its slow metabolism, cold environment, and unique cellular mechanisms. The article also touches on the ecological significance of the Greenland shark in its Arctic ecosystem, underscoring its role as both a scavenger and an apex predator. Furthermore, the narrative underscores the importance of conservation efforts, as the Greenland shark's slow growth rate and late sexual maturity make it particularly vulnerable to overfishing and other environmental threats. The piece concludes by emphasizing the Greenland sharkâs enduring mystique and the continuing scientific quest to unlock the secrets of its remarkable longevity, emphasizing the potential for valuable insights into the fundamental processes of aging and survival.
Summary of Comments ( 35 )
https://news.ycombinator.com/item?id=42746889
HN commenters discuss the Greenland shark's incredibly long lifespan, with several expressing fascination and awe. Some question the accuracy of the age determination methods, particularly radiocarbon dating, while others delve into the implications of such a long life for understanding aging and evolution. A few commenters mention other long-lived organisms, like certain trees and clams, for comparison. The potential impacts of climate change on these slow-growing, long-lived creatures are also raised as a concern. Several users share additional information about the shark's biology and behavior, including its slow movement, unusual diet, and symbiotic relationship with bioluminescent copepods. Finally, some commenters note the article's vivid descriptions and engaging storytelling.
The Hacker News post linking to the 2017 New Yorker article, "The Strange and Gruesome Story of the Greenland Shark, the Longest-Living Vertebrate on Earth," has generated a moderate number of comments, many of which delve into intriguing scientific details related to the shark and the challenges of determining its age.
Several commenters discuss the radiocarbon dating methods used in the study, specifically focusing on the impact of nuclear testing on carbon-14 levels in the ocean. This discussion highlights the complexities of accurately dating marine organisms, particularly those living for extended periods, as the "bomb pulse" of carbon-14 from the mid-20th century can skew the results. One commenter explains how scientists had to find a baseline pre-bomb pulse carbon-14 level in the sharks' eye lenses to establish a reliable starting point for calculating age.
Another interesting thread explores the concept of negligible senescence, a characteristic of certain organisms that show no signs of biological aging. Commenters discuss the implications of this phenomenon in Greenland sharks and other species, pondering the potential link between slow metabolism and extended lifespan. One user points out the contrast with other long-lived animals like giant tortoises, which do exhibit signs of aging.
A few comments touch on the dietary habits of Greenland sharks, including their scavenging of polar bear carcasses and the potential impact of changing Arctic ecosystems on their food sources. One commenter even humorously suggests the possibility of Greenland sharks consuming Viking remains, given their long lifespan and the historical presence of Vikings in the region.
Some users express fascination with the extreme lifespan of these creatures and the mysteries that still surround them. Others share additional related information, such as the discovery of a five-hundred-year-old clam and the challenges of studying deep-sea organisms.
Overall, the comments offer a range of perspectives on the Greenland shark, from scientific discussions of dating methodologies and biological processes to more speculative musings on their life history and interactions with the environment. The discussion reflects a general appreciation for the remarkable nature of these animals and the ongoing scientific efforts to understand their extraordinary longevity.