Right Whales Are Endangered, And They Might Have Lifespans Nearly Double What Was Previously Estimated
Right whales are one of the most endangered species of whale on the planet. Now, scientists suggest they might have lifespans that are nearly double what was previously estimated.
New research has deemed southern right whales as the mammal with the second-longest lifespan. The bowhead whale holds the spot for first place. The findings could change the way that conservationists protect whales in the future.
“We are thinking about these whales all wrong,” said Peter Corkeron, a co-author of the study and a marine ecologist at Griffith University in Australia. “It’s impeded our ability to get it right when it comes to doing the science for conservation to stop these whales from going extinct.”
It’s relatively easy to estimate the ages of individual whales, but it’s a lot harder to determine the average life expectancy of an entire species. In the past, one method of doing so involved the analysis of their ear wax. This requires whales to be dead.
Throughout the 19th and early 20th centuries, commercial whaling was intense, so researchers were unable to record the largest and oldest whales.
For the new study, researchers examined photos of right whales from the 1970s. The team identified individual females and made note of when they stopped appearing in the photos, which implied that they had died.
Then, the information was incorporated into statistical models that are similar to the ones used by life insurance companies to estimate the life expectancy of humans. The results suggested that southern right whales have an average lifespan of about 73 years.
However, up to 10 percent of them might live to 131 years old, while a handful of others even approach 150. That is much higher than previously estimated. Before, marine mammals were thought to have a lifespan of 70 to 80 years old.
The same techniques were used to measure the life expectancy of North Atlantic right whales. The species is critically endangered, with only about 372 individuals left alive.
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North Atlantic right whales have a median lifespan of only 22 years. The oldest 10 percent may exceed the age of 47.
The findings demonstrate that whales are still recovering from the damage caused by commercial whaling, a practice that ended around 40 years ago.
“To attain healthy populations that include old animals, recovery might take hundreds of years,” said Greg Breed, the lead author of the study and an ecologist at the University of Alaska Fairbanks. “For animals that live to be 100 or 150 and only give birth to a surviving calf every 10 years or so, slow recovery is to be expected.”
The researchers believe that the life expectancy of North Atlantic right whales is so much lower than southern right whales because of the area they live in.
They inhabit Atlantic coastal waters near the United States and Canada, where lots of commercial activity takes place.
They are also vulnerable to boating accidents and climate change. Meanwhile, the Southern Ocean is much less busy.
In the future, the research team hopes to apply their methods to other whale species. Knowing how long animals live can help experts improve their conservation strategies and better protect them from the threats they face.
The study was published in Science Advances.
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