KDN

This particular shark is believed to predate the existence of the United States of America. A team of scientists discovered a cluster of Greenland sharks and concluded that some of them are the oldest known vertebrates alive today. These sharks inhabit the frigid waters of Greenland and were the subject of a study conducted in 2017, which examined 28 individuals. The eldest shark in the study measured 16.5 feet (five meters) in length and was estimated to be approximately 392 years old. The researchers established, with a "95 percent certainty," that the shark's age fell within the range of 272 to 512 years, with a most probable age of around 390. While the exact reasons behind their exceptional lifespan remain unclear, it is believed that the arctic temperatures they inhabit (plunging below 29 degrees Fahrenheit) contribute to their longevity. These low temperatures result in reduced body temperatures and slower metabolisms, thereby minimizing damage to the sharks' tissues. Additionally, their growth rate is exceptionally slow, with less than half an inch (a centimeter) gained per year, suggesting a significantly longer lifespan compared to other vertebrates. Furthermore, the females of this species exhibit delayed sexual maturity, only beginning to mate at the age of 156.