Black, White, and Red All Over: Orcas Penetrate the High Arctic

You could say I have shifted a lot of my attention and interest onto aquatic stuff lately - hey I included the word salad in the name of this blog for a reason, a salad can have all manner of toppings including seafood!! So no plesiosaur machinations today nor spinosaurid stuff although plenty more to come this year in those regards so stay tuned. No today I want to focus on extant marine creatures/ecological communities of the Arctic. Namely recent range expansion of what I consider personally the penultimate marine predator of all time (sorry Megalodon fanboys), the killer whale or Orcinus orca while Ursus maritimus - the polar bear - diminishes.

 Orcinus orca. Uploaded by EvaK. CC 2.5 Senckenberg Museium Frankfurt Germany

The polar bear, Ursus maritimus, has become a bit of a symbolic linchpin for anthropogenic global warming. As a top predator at the top of the world which is inherently dependent on pack ice as a platform to hunt it's more aquatic capable phocid prey this choice is an obvious one. As the ice goes, so does the polar bear. And in our ramped up, high velocity anthropogenically driven world ecosystem there is a bit of an asteric at the question of polar bears surviving in an increasingly ice free Arctic - can they even adapt that fast with the pace of current climate change? I do lay out one possibility here. Never the less we should not consider the possibility of an ice free Arctic or the extinction of the polar bear as the end of an "ecosystem" so much as merely the start of a strange, new one. And quick to move into and usurp the polar bear as king of the Arctic is the killer whale, a shifting of the guard we may in fact be witnessing currently and which might become a veritable reality in this century.

credit CJBLYTHE

Compared to the three most notable Arctic whales (bowhead, beluga, and narwhal) the killer whale is at a bit of a disadvantage in ice- it has a huge dorsal fin, especially among the males where it might be 2 meters tall. So although they do move up to the edge of the pack ice in the Arctic and Antarctic they do not penetrate very far into the pack ice or areas with large amount of floating ice due to obviously painful scrapings and cuts that constant abrasion against ice would incur. So not only is ice a hunting platform for polar bears and a resting/birthing stations for seals - it a sanctuary of sorts for Arctic whales from killer whales. But a spate of incidents suggests that the sanctuary that ice provided whales in the high Arctic Canadian archipelago and Hudson Bay is no more. There is a bloodbath in paradise.

Glenn Williams. Narwhals jousting

"We saw this big bloodstain in the water", and "You could smell the blubber in the air. And the killer whales were moving onto the next one, like nothing had happened." so describes a witness to an increasingly familiar but previously rare event - killer whales moving into Hudson Bay and targeting beluga whales in the estuaries and bays that they traditionally stayed in during the summer months in relative safety. Orcas Pop Up near Churchill, Feed on Beluga.  What was at most an ephemeral and rare predatory encounter between the two species is looking more and more like a deliberate hunt by the killer whales. The ice disappears earlier and arrives later allowing the orcas to move in and stay longer. There has been the suggestion that some recovering populations are being suppressed and others may be further diminished. Sometimes the killer do not make it out of the Bay in time, as occurred last year when a pod was trapped - but eventually freed by currents.

photo credit Davidee Mina. killer whales trapped Hudson Bay

What is obvious is that killer whales are increasing their presence in the Arctic, especially the eastern Canadian Arctic, and that they are targeting more than just belugas.

Invasion of the Killer Whales. Nature PBS December 18, 2014.

The portrait painted by the above highly recommended Nature documentary is one of an ecosystem in flux. Polar bears scrounging for carcasses on the beach, sea bird eggs, and fishing for Arctic char in rivers. And killer whales moving into an ecosystem in which they had previously been kept at bay. Moving with a purpose, covering over 200 km a day to seek out narwhal populations in the Canadian Archipelago from which they could not reach before. Bowhead whales evincing massive scars and bites from killer whales and switching their movements towards areas that retain ice year round to avoid the killer whales. Playing a game of cat and mouse the two whales listen to eachother across vast expanses of ocean.

Tagged killer whales (red) versus tagged Bowhead whales (yellow) showing avoidance patterns

Bowhead fluke w/killer whale maulings

And a third archpredator of the Arctic, Homo sapiens of the Inuit culture, seeking answers and context to an archpredator which had only previously been an ephemeral visitor but which now increasingly shapes the prey and the ecosystem that they are dependent on. Will the seals and whales that this culture depends on shift range and habits to deal with their new predator? How will this affect the ability of these people to find them? Are we looking at an example of killer whales competitively excluding humans?

"I was hunting these narwhals and they were fleeing from some killer whales. The killer whales were travelling fast and upside down. And they breached the water chasing the narwhal. When they got close to the shore where the narwhal were they took bites out of two of them very quickly. This is when I realized that they are supreme hunters." Inuit elder.

"We knew changes were happening and wanted to understand them... We anticipated a change from the bottom up... We recognized the killer whale as that top predator that was all of a sudden making these huge changes in the Canadian Arctic. And it was something we didn't really think about at the start but there it was staring us in the face." Steve Ferguson, Canadian fisheries biologist on realizing that simultaneous with a bottom up trophic cascade in the Arctic a top down trophic pressure via killer whales was also occurring.

While killer whales in the eastern Canadian Arctic appear to be expanding their range to include areas westward and northward and capitalizing on prey/feeding grounds previously out of their reach between Alaska and Siberia on a group of islands called the Diomedes they have been documented predating on walrus recently. The following clip I scrounged up on Youtube is to the best of my knowledge the first video documentation of such an occurrence.

Walrus, which are themselves recognized as keystone species due to the significant bioturbation they do when digging up benthic prey and are significant in the diet of Inuit, are also highly dependent on ice for resting upon. Loss of ice concentrates walrus in large herds on the land which might further enable killer whales to find and target these large seals.

Polar bears have also been documented targeting these concentrations of walruses, although concentrating usually on the young. Another food source grounded polar bears have been utilizing during the summer months are runs of a type of arctic salmon called arctic char.

Polar Bears hunting Arctic Char. Nature

 Harkening back to their brown bear roots...

Global ecosystem change is already afoot. Some will adapt. Some will move. Some will benefit. And some will perish. How this will all play out and what surprises await who can say?

(c)US Navy. public domain. USS Honolulu 450 km (280 mi) from N. Pole

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Paleo Myth Number 1: The Past Was More Awesome Than the Present

Now I might get some slack for saying this, maybe some paleo-nerd rage directed my way, but I don't think Megalodon is worthy of all the bad-azzery attributed to it. Why would I say this? Well first of all, the morphology and physique given to Megalodon is basically a scaled up great white, a conjecture we have no proof of save the similar tooth design. Instead of the homocercal tail that great whites utilize for rapid cruising and sustained acceleration augmented by endothermy, how do we not know that Megalodon had a heterocercal tail for slow cruising and ocassional short bursts of speed? What if Megalodon was not, like the great white, endothermic at all? * But I am going to venture that the greatest weakness of all for Megalodon is in fact the accolade most generously heaped upon it- it's size.

Now it does not really matter where you end up on the spectrum between the grey and red one, you still have a very large fish- probably among the largest fish that ever existed. But this brings up an interesting pattern, why do all the largest fish cluster around this 40-60 foot range? The largest predatory sharks, the largest filter feeding sharks, Leedsichthys and it's ilk of Mesozoic filter feeders- they all seem to cluster around this size but fish never truly reach blue whale size despite having a much longer tenure in the ocean to do so.

Martill. 1986. Leedsichthys and Liopleurodon

The answer, as succinctly as I can put it, is that as size increases in an organism the volume increases disproportionately faster. And this holds true if you are a single cell organism trying to diffuse wastes across a permeable membrane or if you are 30 tonne shark trying to supply oxygen throughout your body with a limited surface area (gills) for gas exchange. As Megaladon, and other giant fish, got larger and larger they start running into problems. Their volume is increasing exponentially while their surface area is increasing linearly. And the amount of area they have for gas exchange, their gills, is a function of their surface area and therefore not increasing at the same rate as the volume. What you have therefore is a whale shark, or a Leedsichthys, or a Megalodon that is approaching a size of diminishing returns and eventually a glass ceiling for gill-breathing animals. These mega-fish, I would argue, are not  sustained aerobic fast cruisers, had minimal endurance, probably slow metabolisms and essentially became dead in the water if pushed too hard. If you want to picture how Megalodon swam around, the video below of a whale shark going after a bait ball offers more insight, I believe, than modern hunting 1 tonne great whites do breaching after agile pinnipeds.

Megalodon succeeded because it lived at a time when their was just enough slow swimming marine mammals, abundant carcasses, and lack of competition from derived predatory pack hunting toothed whales to exist. It was limited to probably warm temperate seas and was basically good for one or two quick lunges at prey, but not extended chases like modern great whites engage in. When derived, social, and intelligent toothed whales came on the scene it was in trouble. Unable to out-swim or out-manoeuvre a couple of well placed strikes at the gills by these marine mammals and a tip into tonic immobility spelled doom for the last Megalodon just as it does today for many sharks at the hands (flippers) of killer whales. The feasts of liver ripped from Megalodon must have been a sight!!

Killer Whale w/Mako Shark. Visser/Barcroft (c)

Ok I will stop savaging the myth of Megalodon, the supposed marine bad-ass of all time. Admittedly I am playing devil's advocate a bit here- of course I would love to see a Megalodon, it probably is near the top of my all time list of extinct critters I would love to see alive. It must have been an amazing spectacle. But what I am trying to illustrate here, what I am getting at, is that we often fetishize the past at the expense, or ignorance, of the present. We build up these monsters of the past into fantastical, mythical god-creatures- when in reality they were just animals, with strengths and weaknesses all of their own. I could have easily started by debunking pseudo-mythical velociraptors, tyrannosaurs, Sarchosuchus, or Spinosaurus. What you must keep in mind when comparing past organisms to present  ones, is that we tend to look at the whole pantheon of awesome extinct animals- and cherry pick the most outrageous ones- and then compare them to the small finite sample available in this little slice of geologic time. And although our land fauna is very impoverished compared to the Mesozoic or even 10,000 years ago- our marine megafauna, especially whales, dominate all other epochs in terms of size, growth, and amazing feeding styles- lunge feeding baleen whales, super intelligent pack hunters, sonar aided hunting.

I'm sure everyone remembers the hoopla surrounding that god-awful faux-documentary about a live Megalodon and all the blowback discovery channel got for it? You know when shark week, umm, jumped the shark (sorry)? Well at about the same time everyone was ranting and raving about that horrible show on Megalodon during shark week, for a critter I argue has been hyped up beyond recognition, real science about a real arch-predator of the ocean was being published that did not garner 1/100th the attention the Megalodon debacle did. And this was the revelation that a whole new species of killer whale, the type D genotype, is alive and well and swimming around the southern oceans as we speak. A whole new species of killer whale!!! No discovery channel special!! No nat-geo special!! No media hoopla!!! Hardly any fanfare to speak of for a whole new species of multi-tonne marine arch-predator!!

Type D killer whale. Jean Pierre-Sylvestre. Nat Geo (c)

And here is where I want to crystallize my argument. And this is the case that not only are orcas super awesome marine predators, they are the baddest of the bad when it comes to marine arch-predators of all time. A cultured, highly intelligent, pack hunting, echo-locating, tool using, matrilineal, fast, strong, and persistent cosmopolitan family able to launch attacks on everything from schooling fish to herds of sperm whales and even the largest animal ever, the blue whale. Adult males are as large as t-rex and at least as intelligent as the average Wal-mart shopper. I put them over Megalodon, over Pliosaurs, over giant extinct raptorial sperm whales, over great whites which they casually snack upon, over mosasaurs. I believe they would find a way to kill each and every marine arch-predaor that lived before them. And they live with us right here right now. Yet we stuff them into unnatural concrete enclosures and wonder why they go insane and kill us. And when a whole new species is discovered we hardly take notice and pay respect to the all time maritime king.

Shame on us.

* Amendment 9/9/13. It has come to my attention that there is a paper Dermal scales of Carcharocles megalodon from the Miocene Mizunami Group, Central Japan! Author Hiroyuki Nishimoto et al 1992. Bulletin of the Mizunami Fossil Museum that purportedly shows evidence of placoid scales suggestive of high speed, fast growth and perhaps endothermy. I have not seen/or read the paper but it does exist. I don't claim to be a specialist in shark evolution, merely a fan. However I don't think this invalidates one of the premises of my article concerning gill surfaces area versus volume increase and the possible eco-physio-behavioral constraints imposed upon such large fish.

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