Whales have some of the longest lifespans in the animal kingdom, with several whale species being recorded as living for more than 100 years.
In the past, researchers have used several methods to measure the longevity of this these marine mammals. They count layers in their earwax, which increase year after year; they measure a chemical transformation in a whale's eye proteins, which occurs at a regular rate.
However, this information can be difficult to get hold of, and often requires a freshly deceased animal to analyse.
Now, scientists have used a different method, which has astonishingly revealed that right whales (Balaenidae family) actually live twice as long as previously thought.
The amazing lifespan of a right whale
Southern right whales, found in oceans below the equator, were thought to live between 70 and 80 years. New research published in the journal Science Advances reveals that their actual lifespan could reach well over 100 years, and 10% may live past 130 years.
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Greg Breed, Associate Professor of Quantitative Ecology, University of Alaska Fairbanks and Peter Corkeron, Adjunct Senior Research Fellow, Centre for Planetary Health and Food Security, Griffith University, were co-authors of the research paper. They revealed that they used photo identification of individual female whales over several decades.
"Individual whales can be recognized year after year from photographs. When they die, they stop being photographically "resighted" and disappear," they explained in ScienceAlert.
"Using these photos, we developed what scientists call "survivorship curves" by estimating the probability whales would disappear from the photographic record as they aged. From these survivorship curves, we could estimate maximum potential lifespans."
The data revealed that Southern right whales can live for more than 130 years, with some speculated to reach the grand old age of 150.
Negative impact of humans on North Atlantic right whales
The research also uncovered information on the devastating impact of human behaviour on North Atlantic right whales, which are native to the Atlantic coast of North America.
The two species are so similar they were once thought to be the same. Now the North Atlantic right whale is one of the most endangered of all large whales, with no signs of recovery despite protection from whaling since the 1930s.
This species was thought to also live to around 70 years. However, the new research has revealed that the current lifespan is only 22 years, and that they rarely live past 50. The reason is thought to be death by entanglement in fishing gear and ship collisions.
Why studying whale lifespan is important
Greg Breed and Peter Corkeron reveal that understanding how long wild animals live helps us protect them.
Conservation and management strategies that do not plan according to a whale's lifespan – which is directly connected to reproduction timescales – will have a higher chance of failure, they say.
The longest-living whale
The bowhead whale is thought to be the longest-living mammal, with some whales living to over 200 years.
Scientists believe that living in Arctic conditions is the reason for the bowhead’s slow growth rate and longer life. It's also thought that these whales have unusually effective DNA repair processes, which can reduce them developing terminal diseases, such as cancer.
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Main image: Southern right whale. Getty Images