Tag Archive: transient killer whales


Dr. Michael Bigg

Super hero – Dr. Michael Bigg. Achieved so much before passing at just age 50 (1939 to 1990).

What’s the Bigg’s Deal?  I’ve been asked this a lot lately: “Why are the mammal-hunting killer whales being referenced as “Bigg’s killer whales” rather than as “transients” as they were previously known?”

This is because a 2010 study found that the mammal-hunting ecotype of killer whales diverged from the other ecotypes some 700,000 years ago and the researchers (Morin et al) put forward that they be recognized as a distinct species.

If they are to be recognized as such, many in whale-research-world believe it is only appropriate that the species be named in honour of the late and great Dr. Michael Bigg whose pioneering killer whale ID research in the eastern North Pacific in the 1970s – 1980s revealed that killer whales have distinct populations and that there are very limited numbers within these populations.

Ultimately, his research led to the understanding that killer whale populations have distinct cultures.

This knowledge of course had huge conservation implications. It was previously believed that there were abundant killer whales in the eastern North Pacific and that they all ate salmon in addition to marine mammals; rather than the reality that there are four at risk populations that are genetically and ecologically distinct:

  • 1.  Bigg’s killer whales are marine mammal-hunters (they also eat an occasional bird and, very rarely, a terrestrial mammal). The population estimate for this threatened population is 270 individuals that are more often along coastal BC, with research ongoing regarding population numbers further off the coast. Their behaviour has changed since recent years of study, as reported by colleague researchers at the Marine Education and Research Society.   They are not so “transient” anymore. In some areas they are more commonly sighted than “residents” and appear to be travelling, socializing and hunting in bigger groups. They also appear to be more vocal, especially after a kill.  This may be due to changes in the location and density of their prey. Status report and further information here.
  • “Residents” are inshore fish-eating killer whales (ingesting an occasional squid too) and there are two distinct populations. The vast majority of their fish diet is salmon and of the salmon species, their absolute favourite is Chinook.
    • 2. The northern “residents” are a threatened population of some 260 whales more often found in northern British Columbia but also in southeastern Alaska and Washington State. Status report and further information here.
    • 3. The southern “residents” are most often swimming around southern British Columbia and Washington State but are sometimes also in the waters of northern British Columbia, Oregon and California. At only 81 individuals, this population is recognized as being endangered. Status report and further information here.
  •  4. Offshore killer whales are fish-eaters often found along the continental shelf from the Aleutian Islands to California. To date, published research has confirmed that their diet includes Pacific sleeper sharks and Pacific halibut. The population estimate is in the range of 240 to 340 individuals and this too is a threatened population. Status report and further information here. 

Through the research of Dr. Bigg, the killer whales of British Columbia have been studied as individuals longer than any other marine mammal species on the planet – and not only marine species have benefited from this. We all have.

Due to his work, whereby the age, gender, diet and range is known for almost every killer whale in British Columbia, these whales “tell the story” of global chemical pollution. The work of Dr. Peter Ross examines the toxins in the blubber and indeed the killer whales of BC are the “canaries in the coal mine” informing the science that should shape international policies and regulations regarding toxins.

However, there is also much that has NOT changed since the days of Dr. Bigg’s pioneering killer whale research. 

At that time, killer whales were the scapegoat for declining salmon populations and the “gold rush” on their being put into captivity was likely perceived as a favourable management tool.  Conservation costs money, not only for science and management, but also by limiting industries whose activities may negatively impact species at risk.

Flash forward some 40 years to 2013. Dr. Peter Ross’ work with Fisheries and Oceans Canada has been terminated as part of what can only be called the demise of Canada’s ocean contaminants research program and prior to his termination he, like so many other government scientists in Canada, has been constrained in being able to communicate about his research.

The ultimate Bigg’s Deal is that one person can make a profound positive difference – replacing knowledge where fear and misunderstanding once dwelled.

However, to work against government forces that imperil our environment and suppress science in favour of short-term economic gain, it is going to take a very great many of us to make our voices and actions . . . Bigg-er. 

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For more information:

What's the Bigg's Deal.001.001

Research of Dr. John Ford and Graeme Ellis on the diet of mammal-hunting killer whales in the Northeast Pacific Ocean. Source: Presentation "The Complicated Predator" by Dr. Lance Barrett-Lennard; October 2005.

Research of Dr. John Ford and Graeme Ellis on the diet of mammal-hunting killer whales in the Northeast Pacific Ocean. Source: Presentation “The Complicated Predator” by Dr. Lance Barrett-Lennard; October 2005.

This is not a tall tale. If anything it is a short tail as in – deer tail.

First an orientation on killer whale diet and how prey specialization has shaped distinct cultures over great expanses of time. 

Different populations or “ecotypes” of killer whales do not mate with one another because what works, for example, to chase salmon does not work to stalk seals.

The fish-eating killer whale ecotypes in the NE Pacific (“residents” and “offshores”) can afford to be extremely vocal because fish species often have poor hearing.

However, the mammal-hunting killer whales (“Bigg’s killer whales” previously know as “transients”) must generally live a life of stealth and unpredictability in order to successfully hunt their prey. To be vocal or be really surface active would have a high cost. It would be like ringing a dinner bell announcing “Hello, we’re here to eat you!”

In fact, recent research supports that the NE Pacific mammal-hunters diverged from the other ecotypes of killer whales some 700,000 years ago and puts forward that they should be recognized as a distinct species (Morin et al 2010).

Seals are predictable in where they haul out and they do not have defences like speed and sharp teeth. Therefore, it is not surprising that off the coast of British Columbia, Pacific harbour seals are documented to be the prey item of choice for the mammal-hunting killer whales (see graph above). 

Less commonly, these killer whales have also been documented to feed on river otters, elephant seals, sea otters and – an occasional terrestrial mammal like deer. 

Please see below for images of a deer carcass found underwater by fellow divers Gary Marcuse, Rob Roy and Mike Juren in May of 2012. There is no way of  knowing with certainty if that this deer was attacked by killer whales but it is plausible. Deer swim from island to island and are even more defenceless than a seal if they have the bad luck that stealthy mammal-eating killer whales find them. 

Deer-Underwater

Killer whales are big dolphins – smart and social and even though they tend to be very conservative, doing what has worked for their kind for 100,000s of years, they also play – learning from interacting with their environment. I have reflected on this previously in my blog where I observed them mouthing and hitting diving birds. (Read “Fins vs. Feathers” here). 

Deer could never make up a significant part of their diet but the killer whales would learn from such an attack. If this deer did indeed meet its end in the mouth of a killer whale, I would not be surprised if it was a juvenile mammal-hunting killer whale who undertook the “interaction”.  

To share the expertise of killer whale researchers supreme, Dr. John Ford ad Graeme Ellis, from their 1999 publication “Transients -Mammal-Hunting Killer Whales:  

“Although the primary prey of transient [now Bigg's] killer whales are marine mammals, the whales’ interest extends to other warm-blooded animals, including marine birds .  . . and even terrestrial mammals. Our first record of land mammal predation dates from June 1961, when Canadian fishery officers observed killer whales feeding on a deer carcass in Jackson Pass on the central coast of British Columbia. Deer frequently swim from island to island along the inside passages, and it is probable that this one fell victim to a foraging group of transients. More recently, off the east coast of Vancouver Island, several killer whales were observed circling a small rock on which two deer had taken refuge. On another occasion, a lighthouse keeper assisted an exhausted deer out of the water as it was being pursued by killer whales. In these case, there has been no photographic confirmation that transients were involved, but it seems almost certainly the case.

Other land mammals are also of interest . .  on occasion . . . a killer whale was observed to surge part way onto shore in an apparent attempt to attack a dog that was barking loudly at the passing group.  . . .

One of the most surprising attacks on a terrestrial mammal took place in 1993 in Icy Strait, south-eastern Alaska. Two fishermen observed a group of three or four killer whales attack and kill one of a pair of moose that were swimming across the channel. The other moose managed to escape the attack but later became entangled in a kelp bed and drowned.”

So am I worried, as a very avid and very mammalian scuba diver, that I have the same chances of being attacked as a deer swimming between islands? Absolutely not. There has never been a case of killer whales in the wild killing a human. 

To again relate John Ford and Graeme Ellis’ expertise:

” Divers in this region typically wear thick suits made of neoprene rubber, which contains acoustically reflective nitrogen bubbles. Thus, if a transient [Bigg's killer whale] tires to inspect a diver with echolocation, its unlikely to get a typical mammalian echo. Although scuba divers may not appear appetizing to [them], this may not be the case for swimmers, so it is advisabel to leave the water should transients [Bigg's] appear in the vicinity.” 

I also love the perspective of a fellow diver and friend, Peter Mieras, who states that killer whales “are too smart to go after junk food in wrappers.” 

Oh deer! 

For more information on the different populations of killer whales in the North-eastern Pacific, see the BC Cetacean Sightings Network page by clicking here. 

Sources:

Transient killer whale grabs rhinoceros auklet. See slide show below. Photo: Hildering. All photos taken with telephoto and cropped.

From the evidence I deliver in the slideshow below, you’ll see that August 31st, 2011 was not a good day for some rhinoceros auklets (Cerorhinca monocerata) in Johnstone Strait, British Columbia, Canada. 

That day, I witnessed a very socially active group of “transient” (marine mammal-hunting) killer whales repeatedly harassing these birds - mouthing them and slapping them. At least 3  juvenile rhinoceros auklets had a bad day and, since these are diving birds, they cannot “alight” and escape the teeth and fins below them. Yet, I believe they survived.

I interpret the transient killer whales’ interaction with the birds to be “text book” play behaviour largely involving the juvenile killer whales. In this case, the text book is Dr. John Ford’s and Graeme Ellis’ Transients: Mammal-Hunting Killer Whales of British Columbia, Washington, and Southeastern Alaska. I provide their  expert interpretation of the behaviour below, entitled “Seabirds: Playthings and Practice, or Between-Seal Snacks?” 

Transient killer whale surfaces right beside rhinoceros auklet. See slideshow below. Photo: Hildering. All photos taken with telephoto lens and cropped.

“It is not unusual to see transients chasing and harassing seabirds. During most of these incidents, the whales do not seem intent on eating the birds. Rather, they let the bird escape or they abandon it after it has been injured or killed. Seabird harassment appears to be a favourite activity of juvenile transients. They young whales will sometimes swim upside down and on their sides, looking for birds paddling at the surface above. Once a victim is sighted, they will try to slap it with their tail flukes, jump on it, or seize it in their mouth. This interaction may continue for several minutes, before the bird is eaten, incapcitated, or left dead in the whale’s wake. We and others have recorded at least 10 seabird species that have become casualties of transients. Frequent victims are common murres, which are flightless for several weeks during the late summer and are like “sitting ducks” for transients.  Other species include black brant, common loon, white-winged scoter, surf scoter, cormorant (species uncertain), western grebe, marbled murrelet, rhinoceros aucklet, and red-breasted merganser.  Seabirds seem to be more important as objects of play or harassment than as a dietary item. Juveniles playing with seabirds no doubt learn useful skills in prey capture and handling that may enhance their success in hunting harbour seals and other wily prey.”  Source: Ford, J.K.B., and Ellis, G.M. 1999. Transients: Mammal-Hunting Killer Whales of British Columbia, Washington, and Southeastern Alaska. UBC Press, Vancouver, and U. of Washington Press, Seattle. 96 pp

Transient killer whale tail-slapping a rhinoceros auklet. See slideshow below. Photo: Hildering. All photos taken with telephoto lens and cropped.

I personally had never seen such a prolonged display of this transient killer whale play behaviour before. In fact, I had never seen transient killer whales socialize quite so rambunctiously!

 In the Northeast Pacific, “transient” killer whales (or “Bigg’s killer whales” – after the late Dr. Michael Bigg) are believed to have diverged from the “resident”  (inshore fish-eating) and “offshore” (offshore fish-eating) killer whales some 700,000 years ago (Morin et al, 2010), to refine a culture of stealth and unpredictability in order to hunt their marine mammal prey.

But clearly, when their bellies are full and social needs dominate, this type of killer whale is anything but stealthy. On August 31st, this incredibly socially active group of 20+ transients took about 1.5 hours to travel only +/- 4.5 km (2.5 nautical miles) – slapping birds, rolling over one another, tail slapping, vocalizing and breaching along the way. The whales would go on to bound past the community of Alert Bay, Cormorant Island. I have have previously written about this in the blog item “Might As Well Jump.” 

Jared Towers of the Department of Fisheries and Ocean has confirmed the IDs of the transient killer whales in the August 31, 2011 encounter to be:  T010s, T034s, T035s, T037s, T046Bs, and T146s.


Photos taken while on board with Orcella Expeditions. 

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