How long do orcas live?
There are many questions about how long orcas live in captivity compared to how long they live in the ocean. In the 2013 documentary film Blackfish
Howard Garrett said the following:
"We knew by 1980, after a half a dozen years of research, that they [killer whales] live equivalent to human life spans."
The data are clear that orcas in captivity suffer from extreme stress, injuries, disease and infections, and survive on average less than ten years in captivity
. According to research done in 2011 by The Orca Project:
Marine parks such as SeaWorld tout their ability to provide environments adequate to keep orcas alive. However, this claim is not supported by the evidence. Approximately 157 orcas have died in captivity, not including stillborns and miscarriages. Based upon the MMIR data, and represented in Appendix A, we have calculated the mean duration of captivity (MDC) to be less than nine years. This is regardless of whether an orca was extracted from the ocean, or born at a theme park.
SeaWorld's explanation of longevity comparisons
between wild and captive populations states: "The issue of killer whale lifespan is one that is often misconstrued and overly simplified. The simple truth is that no one knows." But then they go on to say that they do know: "The data we do have show that killer whales at SeaWorld are living as long as their counterparts in the wild. "
But how long do they live in natural habitats? A 2005 paper by Olesiuk, Ellis and Ford
listed the following life expectancies:
46 years for Northern Resident females from 1973 to 1996 and 30 years from 1996 to 2004; 50 years for Southern and Northern Resident combined females from 1973 to 1987; 39 years for Southern Alaska Resident females from 1984 to 2001; 31 years for Northern Resident males from 1973 to 1996 and 19 years from 1996 to 2004; 29 years for Southern and Northern Resident combined males from 1973 to 1987; and 31 years for Southern Alaska Resident males from 1984 to 2001. (The complete breakdown is in Table 14 on page 55.)
The 2005 Olesiuk et al paper is the best summary of orca lifespans to date with hard data. One important caveat however, is that those data are from a population that was quite likely significantly culled by random shootings prior to the start of the field studies. The estimates in Olesiuk et al are based on observations beginning in 1973, and mortalities from shootings may have been high for decades prior to that date, which could have significantly biased the lifespan estimates downward, because the killed animals would have added to the ranks of older age classes during the study if they had not been killed. Olesiuk et al, p. 4:
...it is possible substantial numbers may have been injured or killed opportunistically by fishermen, fisheries personnel, and sportsmen during an era of widespread predator control. Bullet wounds were evident in up to 25% of the animals taken during the live-capture fishery in the 1960s and early 1970s (Keyes cited in Hoyt 1981).
Another important caveat to qualify the data in Olesiuk, et al., is the effects of persistent toxins on lifespans. For this see: Ross, et al., High PCB Concentrations in Free-Ranging Pacific Killer Whales, Orcinus orca: Effects of Age, Sex and Dietary Preference (2000)
. See especially Figures 2 and 3 to see that No. Residents show high levels of these toxins (mostly blown in by wind currents from Asia), which could have significantly reduced the lifespans described in the data in the 2005 paper. These toxins tend to compromise immune systems, especially when combined with food shortages.
Garrett's estimate in the movie of the probable lifespans of free-ranging orcas in natural habitats worldwide is based partly on the data in those papers, given the above caveats, but also on some rather astounding parallels in the phases of life for orcas and humans.
A 2012 paper by Emma Foster et al.
describes something briefly discussed in the 2005 paper: female reproductive senescense, or menopause. A striking similarity between humans and orcas comes clear in the female post-reproductive lifespans.
Orcas and humans (and pilot whales) are the only mammals known to science (so far) to exhibit menopause. For both humans and orcas, females are reproductive for about 25 years until around 40 years of age, but often live 3 or 4 decades after their last offspring is born. In natural orca communities where mating is governed by cultural traditions (along with diet, language, etc.), the first calf is born when the mother is about 14-15 years old. Most human females are capable of having their first baby at about that age. At SeaWorld, females are often bred much earlier, at 6 or 7 years old, indicating either artificial inducement by hormonal supplements, or the absence of cultural restraints, or both.
We don't have definite birth years for the older orca females, but several have been post-reproductive since the photo-ID studies began in 1973, and are still alive, indicating they are at least around 75 now, and some are older. That is roughly equivalent to human life spans.
Olesiuk, et al., p. 33:
It has become clear that killer whales can live much longer than the 25-30 years suggested by annuli in teeth (Mitchell and Baker 1980; Christensen 1982, 1984) or survival rates of captive animals (Small and DeMaster 1995). Most of the females that were in their teens when our study began 3 decades ago, are still alive today. Indeed, several of the females that were post-reproductive, suggesting they were at least in their 30s or 40s when the study began, are still alive.
Male maturation rates are also very similar for humans and orcas, beginning in early to mid-teens with full maturity in late teens. This indicates that full male lifespans in undisturbed populations may also be similar.
Absent the pre-1973 mortalities from shootings, and the toxic contamination from persistent organochlorine pollutants, the data would have shown many more females in their 80s and 90s or more, and more males in their 60s and 70s or more, about equivalent to human lifespans. It's entirely possible they could have even longer lifespans.