How long can right whales live? Study extends their lifespan estimate
Scientists had believed Southern right whales have a lifespan of about 70 years, but a new study shows that endangered mammals can live twice as long as they had thought. The study found these whales often reach 130 years old and may even live up to 150 years.
Right whales are among the rarest whales on the planet, and their populations are highly endangered. The new findings, published on Dec. 20 in the journal Science Advances, indicate Southern right whales now hold the distinction of having the second-longest known lifespan of any mammal, surpassed only by the bowhead whale. The oldest recorded Alaskan bowhead (Balaena mysticetus) was an estimated 211 years old.
About right whales
Right whales have been listed as endangered under the Endangered Species Act since 1970. The North Atlantic right whale population is estimated at just 372, only 70 of which are breeding females. Entanglement in fishing gear and vessel strikes are the leading causes of North Atlantic right whale mortality.
Longevity of right whales
The Southern right whale has a median lifespan of 73.4 years, and 10% live beyond 131.8 years. The North Atlantic right whale has a median lifespan of only 22.3 years because of human impacts, and 10% survive past 47.2 years. The study suggests that all balaenids and likely most great whales have significant untapped longevity. The potential for extended lifespan has substantial implications for whales' basic biology and conservation efforts.
The whaling industry wiped out many older whales from the world’s population. Right whales were heavily hunted until just the 1960s, when the International Whaling Commission began to ban commercial whaling. People in the whaling industries called them the "right" kind of whales to hunt because they move slowly, have lucrative oil and float when dead.
Where do right whales live?
Southern right whales are found in the Southern Hemisphere, migrating from high-latitude feeding areas in summer to low-latitude breeding grounds in winter. Northern Atlantic right whales primarily are found in Atlantic coastal waters on the continental shelf. Sightings of North Pacific right whales have been reported as far south as central Baja California in the eastern North Pacific, as far south as Hawaii in the central North Pacific, and as far north as the sub-Arctic waters of the Bering Sea and sea of Okhotsk in the summer.
Determining life expectancy
Determining the average life expectancy of a species can be challenging. One difficulty is that traditional methods − like analyzing earwax, which accumulates each year much like the rings of a tree − require the whale is deceased.
In the new study, age estimates were made using photo identification of individual female whales over several decades from 1979 to 2021. Individual whales can be recognized year after year from photographs. When they die, they stop being photographically “resighted” and disappear. Using those photos, scientists developed what they call “survivorship curves” by estimating the probability whales would disappear from the photographic record as they aged. From these survivorship curves, they could estimate maximum potential lifespans.
SOURCE Paste BN Network reporting and research; Science, Advances, NOAA