You’ve seen this clickbait title on The Dodo, I’m sure - “Spotting Of A 103-year-old Wild Orca Was Indeed Bad, Bad News For Seaworld.” Let me tell you. There is no article on that entirely frustrating website that causes me to facepalm harder than that one, except may it’s misleading follow-up: “”Whale Fingerprints”: How We Know Granny The Orca is 103 Years Old.” Sigh.
One of the things I am a huge stickler for is accuracy in science reporting and animal media. These two pieces by The Dodo are examples of the worst kind of perversion of good research; they’re misleading, incorrect, and sadly also have a huge amount of visibility in the middle of a pretty heated debate regarding captive orca lifespans. So let’s talk about what the data about resident killer whale populations actually shows, instead of letting crap like this proliferate in the public consciousness.
For a long time, researchers did agree that Granny (J-2) was probably around 100 years old. They estimated her birth year as being 1911, and that’s still the commonly accepted date that’s listed on most online field ID’s. With the way ages for adult whales were calculated for the southern resident whales at the beginning of the longitudinal study, it made sense. It’s only the most recent research that points towards J-2 being 80-90 years old at best. Here’s how it breaks down.
All of the data on wild southern resident killer whale lifespans and behavior comes from a longitudinal study started by The Center for Whale Research in 1971. At the beginning of the study, the ages of all whales were estimated based on their companions and their size (through photo identification and keeping track of which individuals they were repeatedly sighted keeping company with). Here’s why that works:
Wild resident orcas live in very closely bonded groups called matrilines (related matrilines often keep company with each other in structures called pods). Adult individuals of both sexes travel with their mothers throughout their lives, and so matrilines often consist of 2-3 generations of related females and their children. The only dispersal sometimes occurs when an adult female dies and her adult daughters separate, each taking with her her children and their offspring. This stable social structure helps researchers to estimate the respective ages of whales, as they can accurately establish the reproductive history of females prior to the start of observation.
There’s some pretty fancy calculus involved in the age calculations, but here’s the basics: most females give birth to their first viable calf at a mean age of 14 and have a reproductive lifespan of approximately 25 years - they’ll generally produce a calf every five years. By the time they’re approaching approximately 40 years of age, female southern resident killer whales have stopped reproducing -and that behavioral tidbit helps us estimate their age.
Female whales that appeared to have reached maturity (defined by the researchers as the point at which they rear their first surviving calf, adjusted because of the high rate of neonate and infant mortality) at the beginning of the study had their age calculated in relation to the age of their first calf. Because matrilines often consist of multiple generations, an older whale’s age could be determined by first estimating the age of her last known offspring’s oldest calf. These calculations were all adjusted mathematically for factors such as early or late-onset maturity or the probability of infant mortality.
When the study started in 1971, J-2 was already the size of a full adult. She has never been seen raising any calves, and therefore is assumed to have been of post-reproductive age since the beginning of the study. (Post-reproductive age is defined to have occurred when a whale has been calfless for a decade - whales regularly calve every 5 years while fertile, and an extra five years accounts for the birth and loss of a calf between the yearly censuses). Since most whales have ceased calving 25 years after reaching sexual maturity, that allows us to estimate that J-2 was at least 40 years old in 1971.
J-2’s closest companion at the time was the adult male J-1 (Ruffles), and for a long time it was assumed he was either a sibling, the child of her sibling, or most likely, her oldest calf. This hypothesis was made more likely by the fact that over the course of the longitudinal study J-2 was never seen with offspring. When sighted in 1971, J-1 was already a full-sized adult male with complete dorsal fin development and therefore at least 20 years old - researchers tentatively estimated his birth year as 1950. (He died in 2010 at the estimated ripe age of 59, at the upper limit of the natural lifespan for adult male resident killer whales). If J-1 was J-2’s last calf, born to her at 40 years old in 1950, that would mean that J-2 was born around 1910 and would place her current age at 105.
However, a study done in 2011 that checked genetic samples against presumed paternity in the southern resident population found no direct relationship between J-2 and J-1. The DNA of both whales was included in the study, but when the researchers ran simulations to find probable family relationships based on those samples, none of results suggested any relation between them. It’s not unheard of for adult females to mother orphaned calves after the death of their mother - normally they take in the offspring of related females, but it appears that in some cases (such as L-87 Onyx) they’ll even adopt calves from other pods). In light of the 2011 study, it seems most likely that J-1 was an ‘adopted’ calf of J-2, as he was her near constant companion within her matriline from the beginning of the study until his death in 2010.
This new research means that J-2’s age can’t be determined using J-1’s estimated birth year as her last calf, which mean we’re back to assuming that she was at least 40 years old in 1971. That would place a conservative estimate of J-2’s age currently at 85-90 years old. Is it possible she’s older? Definitely, but it’s not probable. The National Oceanic Atmospheric Association (NOAA)’s census data shows that the average age most adult southern resident females live to is 50 years old and that the known upper bound of their lifespan is approximately 80 years.
Granny (J-2) is still ancient for a southern resident killer whale at past 85, but in light of new research and refined age calculations, it’s highly unlikely she’s over a hundred. While it’s understandable that fans of killer whales would want to celebrate an individual animal for reaching such a venerated age (and that a supposed age of 100 makes a good talking point for arguing against cetacean captivity), continuing to represent J-2 as a centenarian is simply incorrect and devalues what an amazing thing it is that she has already lived longer than most any other individual of her species.
Ford, M. J., Hanson, M. B., Hempelmann, J. A., Ayres, K. L., Emmons, C. K., Schorr, G. S., … & Balcomb-Bartok, K. (2011). Inferred paternity and male reproductive success in a killer whale (Orcinus orca) population.Journal of Heredity, 102(5), 537-553.
Killer whale (Orcinus orca). (2016, February 10). Retrieved April 23, 2016, fromhttp://www.nmfs.noaa.gov/pr/species/mammals/whales/killer-whale.html
Olesiuk, P. F., Ellis, G. M., & Ford, J. K. (2005). Life history and population dynamics of northern resident killer whales (Orcinus orca) in British Columbia(pp. 1-75). Canadian Science Advisory Secretariat.
The Resident Orcas Of J-Pod | Orca Spirit Adventures. (2012). Retrieved April 23, 2016, fromhttps://orcaspirit.com/2012/05/the-resident-orcas-of-j-pod/
Wieland, M. (2011, June 24). Orca Watcher: A Tribute to J1 ~ Ruffles. Retrieved April 23, 2016, fromhttp://www.orcawatcher.com/2011/06/tribute-to-j1-ruffles.html
Wieland, M. (2009, December 09). Orca Watcher: The Story of L87 Onyx. Retrieved April 23, 2016, from http://www.orcawatcher.com/2009/12/story-of-l87-onyx.html