- A new study indicates that right whales have extremely long lifespans of 130 years or more, adding to growing evidence of extreme whale longevity.
- The research draws attention to the plight of North Atlantic right whales, which are critically endangered. It found that despite their long potential lifespan, their actual lives are far shorter than those of southern right whales, a close relative.
- The authors and other experts believe North Atlantic right whales’ lives are being cut short due to threats in the “highly industrialized” waters off the eastern United States and Canada where they live; these include fishing gear, which can entangle the whales, and vessel strikes.
Groundbreaking research in the late 1990s showed that Arctic-dwelling bowhead whales could live more than 150 or even 200 years — longer than any other mammal.
New research, inspired by that work, indicates that right whales (genus Eubalaena) also have extremely long lifespans of 130 years or more.
The study, published in Science Advances in December, not only adds to growing evidence of extreme whale longevity but also draws attention to the plight of North Atlantic right whales (E. glacialis), which are critically endangered. The study found that while they likely could live 130 years or more, their actual lifespans are far shorter than those of their close relatives, the southern right whales (E. australis), likely due to dangers they encounter in the waters off the eastern United States and Canada where they live.
“We infer that both should be able to live to 130 and North Atlantic doesn’t because they’re being killed in crab pots and lobster gear and ship strikes,” Greg Breed, an ecologist at the University of Alaska, Fairbanks, and lead author of the new study, told Mongabay.
A deeply entangled history
A seminal 1999 study analyzed protein in the eyes of dozens of bowhead whales (Balaena mysticetus) to estimate their ages and matched the findings against archaeological evidence: harpoon tips embedded in the blubber of several whales that had last been used in the 1880s. The whales had, remarkably, survived hunts from that era and lived more than another century. One bowhead was estimated to be 211 years old. The research “should have been on the cover of Science,” Breed said.
Narwhals (Monodon monoceros), blue whales (Balaenoptera musculus) and fin whales (Balaenoptera physalus) have all been found to live to more than 100, as well, at least in certain cases. Scientists made those findings despite great challenges to understanding whale longevity. The best method for determining whale age requires freshly dead individuals, which scientists rarely can access. The bowhead research was only possible because of limited whaling by Indigenous communities that’s allowed in Alaska.
It’s taken a long time to recognize whale longevity because populations were decimated by hunting in the 19th and 20th centuries, experts say. In the 18th and 19th centuries, sailing ships, mostly from the U.S “Yankee whaling” fleet, hunted whales globally. These whalers harvested right whales most heavily: They were the “right” whale to target because they moved slowly, floated when dead, and their blubber produced good oil. A period of heavy “industrial whaling” followed from the late 1800s until the 1960s, during which Norwegian and eventually Soviet whalers rose to dominance. They targeted faster species, as right whales had already been overexploited and vessel and weapon technology had improved.
Before the new study by Breed and his colleagues, scientists thought right whales had a maximum lifespan of about 70 to 80 years. These assumptions about whale longevity had arisen toward the end of the industrial whaling period, but by then there were few older animals left, right whales or otherwise.
“It just made it appear that whales didn’t live very long,” Breed said.
The research in recent decades has chipped away at that misperception, but only slowly. Even after the bowhead findings came out, there was a reluctance to acknowledge the possible implications.
“The story for a long time was that bowhead whales were special, they were extraordinary,” Breed said. But “it may be that all whales can live to be extremely old,” he added.
In the case of the right whales, the animals’ misfortune — there are only about 370 North Atlantic right whales in existence, and southern right whales were also scarce until the 1990s — has led scientists to closely observe them since the late 1970s. That long-term work opened the door for the new study.
‘Stark’ differences
Right whale individuals have unique characteristics that make them identifiable, including callosity tissue on the tops of their heads. Individual North Atlantic right whales have long been studied by a consortium of experts who collect and analyze sightings from planes, boats and drones; meanwhile, researchers in South Africa use helicopters to photograph southern right whales near their calving or nursing grounds.
Breed and his coauthors took more than four decades of the data for females of both species and fit it to survivorship curves, which are a commonly used math modeling technique, similar to what’s used by the U.S. Social Security Administration to determine future retirement payments to senior citizens.
The shape of the best-fitting curve indicated that 10% of southern right whales should live to be at least 131.8 years old, but for North Atlantic right whales the figure was just 47.2 years old. The southerns’ median expected lifespan was 73.4 years, but the North Atlantics’ was just 22.3 years.
The disparity was “stark,” according to Philip Hamilton, a senior scientist at the New England Aquarium in Boston who has studied right whales for four decades. Hamilton, who wasn’t involved with the new study, said it showed that the North Atlantic right whales’ median longevity is lower than he would have thought. It “really highlights the impacts of anthropogenic injury and mortality,” he said.
A 2019 study looked at documented North Atlantic right whale deaths between 2003 and 2018. Of the 70 fatalities, scientists could determine a cause of death for 43. Of these, 38 or 88% were due to “anthropogenic trauma”: entanglement in fishing gear killed 22 of the whales and collisions with vessels killed 16.
There’s probably not much of a natural difference in the lifespans of the two right whale species, experts say. The two are phylogenetically very similar and have the same life history characteristics: they begin reproducing at the same age, roughly 12 years old, for example. In fact, they were considered the same species until about 25 years ago. If anything, the study authors wrote, the North Atlantic right whale might possibly have a longer natural lifespan than its southern counterpart, as it’s larger, a trait that tends to track with increased longevity.
Kevin Healy, a quantitative ecologist at the University of Galway in Ireland who wasn’t involved with the study, complimented the authors’ work, saying survivorship models were “really the only way to get at this,” given that the alternative was lethal sampling, which is unethical. He said the models have a high degree of variability, providing a “ballpark” estimate.
A confirmation or refinement of the new findings will come only as decades pass and more data can be collected, all experts agreed.
The North Atlantic right whale’s short lifespan spells trouble for the species’ survival. Though females can reproduce every three years, their calving intervals have stretched to six years or longer, due to the stressors they confront. Breed said that, given their short lives, the calving interval needs to be four years or less “in order for them to simply replace themselves.”
Hamilton warned that North Atlantic right whales were at a “tipping point,” saying “it’s up to us how we can improve their conditions.” He said they live in a “very industrialized ocean” given the grave threats from fishing gear and vessel strikes.
Breed, for his part, said flatly that the outlook was “bad.”
“In the marine mammal community, nobody thinks they’re going to survive,” he said.
Banner image: A North Atlantic right whale named “Kilo” breaches in Canadian waters in 2012. Image courtesy of New England Aquarium, taken under DFO Canada SARA permit.
Critically endangered North Atlantic right whale spotted near Ireland
Citations:
Breed, G. A., Vermeulen, E., & Corkeron, P. (2024). Extreme longevity may be the rule not the exception in Balaenid whales. Science Advances, 10(51). doi:10.1126/sciadv.adq3086
George, J. C., Bada, J., Zeh, J., Scott, L., Brown, S. E., O’Hara, T., & Suydam, R. (1999). Age and growth estimates of bowhead whales (Balaena mysticetus) via aspartic acid racemization. Canadian Journal of Zoology, 77(4), 571-580. https://doi.org/10.1139/z99-015
Sharp, S., McLellan, W., Rotstein, D., Costidis, A., Barco, S., Durham, K., … Moore, M. (2019). Gross and histopathologic diagnoses from North Atlantic right whale Eubalaena glacialis mortalities between 2003 and 2018. Diseases of Aquatic Organisms, 135(1), 1-31. doi:10.3354/dao03376
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