(Photo Credit: Wikimedia)
By Erin McKinney
The story of Granny, the matriarch of the Pacific Northwest’s J-Pod, made her appearance earlier this month and set off buzz for animal lovers everywhere. Why? Because of her age: 103 years old. It also became a rallying cry for anti-captivity extremists who rail against keeping orcas in zoological facilities.
They said Granny’s age clearly proved that lifespans of captive animals were nothing compared to what was possible in the wild.
Very few questioned the validity of the number 103.
To fully understand the nature of killer whale studies, we need to move back in time to the attitudes surrounding killer whales in the 1900s, which was one of fear and misunderstanding. As recent as 1973, U.S. Navy diving manuals read that killer whales were “extremely ferocious” and would “attack humans at any opportunity.” During this period, whales were more valued as machine gun targets then as objects of scientific interests.
One of the first people to begin to change the landscape was Ken Balcomb, who founded the Orca Survey, the goal of which was (and is) to identify and catalogue the Northwest Southern resident orcas. So it was Ken Balcomb, who in 1976, took photos of the orcas from boats, and using some educated guesswork involving offspring estimates, made an estimate that Granny’s age, at the time, was 65.
An estimate of 65.
That guess went unquestioned for 38 years, and now we see The DoDo, and other such notoriously activist centered journalistic sites reporting that Granny’s astounding age of 103 spelled doom for the claims of zoological facilities holding killer whales.
However there are only 2 ways to know the age of a killer whale with certainty: to acquire a tooth sample and examine the layers of dentine, or to witness the animal’s birth and death. Outside of those two means, it is guesswork, albeit in 2014 this is guesswork that has been done for quite a number of years.
But remember that when Granny’s age was determined, it was the first year of this type of photodocumentation, the very definition of a “young science.”
While this age determination is questionable in the first place, there is another piece to the puzzle that is often overlooked. Granny is one individual, in one population, in one well-studied area of the world.
Orcas are the second most widely distributed mammal on earth, and considering the number of populations in existence they are vastly understudied. So even if her age was entirely accurate, she would be a statistical outlier, a blip on the orca lifespan screen, that while it might demonstrate a potential, cannot define the longevity of the entire species.
That’s like taking the oldest human being on record (122 years old) and applying it across the board as a standard.
What is more alarming then even the statistics of Granny is the false sense of security her assumed age seems to impart. The assumption that wild orcas live into the triple digits easily is a dangerous one, and disguises the real problems that the populations are facing. In fact, a 2005 study found that the average (mean) lifespans of the Northern Resident killer whales is actually DECREASING. From 1974-1995, the life expectancy for a female was 46, and a male was 38. However, as the study continued from 1995-2004, it found the average lifespan for a female to be 30 years and males to be 19.
The death rate for those populations during that period doubled, from 2% to 4%.
While the study does state the maximum longevity to be 80-90 years for females, and 50-60 for males, that is a far cry from the average. (Again, back to the 122 year old human.) Much more important is the alarming trend downwards of the whale’s longevity. This is a clear indicator of problems facing the Northern Resident pod, problems that if not addressed could easily prevent us from seeing any more 90-100 year old whales (assuming those to be accurate numbers in the first place.)
The bottom line? Science has been studying killer whales for less then 50 years consistently. Therefore we cannot say for certain that we have 100 year old animals without a dentine sample. The complicated business of age based on photodocumentation, and the complexities of the dozens of orca populations leaves us without a single, neat number with which to answer the question “How long do orcas live?”
Anyone who tells you otherwise hasn’t spent very long looking into it.