Some activists use a claim that is painfully baseless.  Even so-called biologists use this argument.  I want to set the record straight, by using examples, actual observations, and the facts that make this claim misleading.  Dr. Naomi Rose, a self-proclaimed “killer whale biologist” (the reason why I put that in quotes will be discussed in its own post), had a talk an TedX about killer whale social structure; including why she believes it makes this species unsuitable for captivity.  One claim she made during the talk was that inbreeding is “taboo” in killer whale culture, and that captive whales inbreed due to “not knowing any better.”  She cites this as an example of how abnormal captive social structure is.  She is basically implying that orcas have morals and social taboos.  Let’s talk about why this claim is misleading, baseless, and anthropomorphic.  We will mainly discuss the social aspects of incest.

First, there is NO way of knowing what happens in the wild.  Incestuous mating could occur post-menopause – it could also happen when females are not in estrus.  Either of these would explain the supposed lack of inbred wild calves.  But, more on that later.  There’s really no way of observing killer whales and their mating patterns enough to know this.  From the surface of water, researchers can’t get a perfect view of mating.  Sometimes, it can be guessed at (certain “milky substances” have made their way to the surface near a pair of whales on occasion), but we really can’t know who’s mating with who every time it happens.  Even Ingrid Visser isn’t swimming after the whales 24/7, so her great underwater views aren’t capturing lots of whale mating either.   For all we know, related whales are going at it when scientists aren’t watching.  We don’t know enough to confidently say that wild whales never commit incest.  In fact, scientists have said as much themselves!  Brad Hanson, a biologist with the National Marine Fisheries Service’s Northwest Fisheries Science Center in Seattle, had this to say: “’The truth is, we don’t really understand their breeding structure all that well.”1

Why aren’t there as many inbred calves in the wild, though?  As I said earlier – the mating could be happening post-menopause or simply be missing estrus.  Another possibility is that inbred calves are born, but die before the research season (which happens AFTER calf birthing season).  Inbreeding has been suspected to increase chances of calf mortality in cetaceans2, so it’s plausible that inbred calves die before their DNA can be tested.  And even if that weren’t the case, there is NO basis of any kind that can lead to the conclusion that incest is morally “taboo.”  Such a statement is jumping to a highly anthropomorphic conclusion with no factual support.

Now…why may captive whales ACTUALLY seemingly inbreed more?  It is likely due to mate availability. First of all, it isn’t as if conceiving inbred calves is rampant in human care. Nalani is the only case of Mother X Son level inbreeding.  But, we are talking about the social aspect of incestuous mating more than actual inbreeding.  In the wild, killer whales have access to multiple pods of eligible mates within their community, meaning that they can easily mate with unrelated whales.  In captivity, they are restricted to a single pod – their own.  Being highly sexual, they make do with what’s available.   If anything, potential avoidance of incestuous mating in some situations may be a biological instinct.  When unrelated mates are accessible, females may fight off related suitors.  This can be seen in wild wolves.  A breeding male may attempt to mate with his daughters, but they will fend off his advances.3   In that case, it is an avoidance of inbred offspring; rather than a social shunning of the behavior.  Just like orcas, captive wolves will readily mate with their relatives.  Why?  In the wild, wolves disperse to find mates.  In captivity, they can’t disperse. The only way to satisfy their instinct to breed is with their family members.  So they commit incest without hesitation.4  The wolves I know who do this are also sterilized; perhaps they understand that there is no risk of inbred offspring, or they don’t know/care and are simply acting out their urges.  I do not know, and therefore, unlike activists, will not jump to any conclusions.  Similarly, killer whales with a large gene pool available (Northern Residents) appear to have few inbred calves, whereas whales with a smaller gene pool (Southern Residents) do have inbred calves.  Ruffles (J1) had 5 calves within his immediate pod!1   University of Washington professor Sam Wasser  said this in light of a study regarding SRKW inbreeding: “It shows that the population is fairly inbred.”5

 There is much more evidence that suggests incestuous mating is an adaptation to whatever is available than “social taboo.”  To imply that killer whales have social morals is to anthropomorphize.  It is nothing more than an AR ploy to manipulate emotions.

Works Cited

1: With the oldest male whale, “Ruffles,” gone, who will be orcas’ next Big Daddy?


2: In the article “Students on the Case of Dying Dolphins,” students from a local high school broke down the genetic diversity of the Indy dolphins and came to the conclusion that the death of many of the dolphin calves was due to inbreeding. 

3: Rise of Black Wolf Documentary – skip to 29:12.

4: I have personally observed, and heard the observations of others, wolves mating with their close relatives.

5. New worry for orcas in Puget Sound: inbreeding


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