Bowhead whales (Balaena mysticetus) are capable of living 150 years or more, a record only surpassed by their neighbor, the Bowhead shark (Somniosus microcephalus), which thanks to a slow metabolism influenced by the low temperatures of its environment, Furthermore, as an extraordinary regeneration of DNA, it holds the record among vertebrates at almost 300 years old – although it is believed that these estimates are too conservative and could even reach half a millennium.
Now, to the group of ‘methuselahs’ of the sea we must add a new species: the right whale (Eubalaena australis). New research published in the journal ‘Science Advances‘ reveals that these cetaceans can survive for more than 130 years, almost double what was previously believed.
Right whales, which are much more closely related to bowhead whales than any other species, appear to have a lifespan similar to that of their relatives. Both species filter food through their baleen and migrate seasonally to give birth. Whalers considered them the ‘proper’ whales to hunt because of their thick blubber, which made them float when killed.
The current study examined four decades of data collected by photo identification programs that tracked individual whales of two species: the southern right whale, which lives in oceans south of the equator, and the critically endangered North Atlantic right whale. , which is located along the Atlantic coast of North America. The researchers used the data to construct survival curves (graphs that show the proportion of a population that survives at each age) similar to those used by insurance companies to calculate human life expectancy.
Obvious vital differences
The analysis revealed that southern right whales, which were previously believed to live only 70 to 80 years, can live over 130 years, and some specimens can live up to 150 years. Instead, the study found that the average lifespan of the North Atlantic right whale is just 22 years, with very few individuals surviving beyond 50 years.
According to Greg Breed, an associate professor at the University of Alaska Fairbanks, the stark contrast in the lifespans of these two closely related species is primarily due to human impact. “North Atlantic whales have an unusually short lifespan compared to other whales, but this is not due to intrinsic biological differences, and they should live much longer,” Breed notes. “They often become entangled in fishing gear or hit by boats, and suffer from starvation, possibly related to environmental changes that we don’t fully understand.”
The study has important implications for conservation efforts. “To achieve healthy populations that include old animals, recovery could take hundreds of years,” Breed said. “For animals that live to be 100 or 150 years old and only give birth to a surviving offspring every 10 years or so, recovery can be expected to be slow.”
Importance of cultural knowledge
The study also highlights the importance of cultural knowledge among whale populations. «There is a growing recognition that recovery is not just a question of biomass or the number of individuals. It’s a question of the knowledge that these animals pass on to the next generation,” says Breed. «This knowledge is not only genetic, but cultural and behavioral. Older individuals teach survival skills. “Younger animals learn by observing and copying the strategies of older ones.”
Breed and his colleagues aim to expand their research to other whale populations and predict whether other whale species currently thought to live around 80 years may also have much longer lifespans. They hope to learn more about how whaling affected the number of old individuals in current whale populations and predict when their numbers will recover to pre-whaling levels.
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