Tag Archives: Kodiak Island

What is a Kodiak Bear?

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The question I am most often asked about Kodiak bears is, “What is a Kodiak bear, and how does a Kodiak bear differ from an Alaskan brown bear or a grizzly bear?” This is a good question, and it does not have an easy answer.

From a taxonomic standpoint, all North American and Eurasian brown and grizzly bears are grouped into one species, Ursus arctos.  The bears of the Kodiak Archipelago are further subdivided into the subspecies Ursus arctos middendorfi , and all other brown bears, including grizzly bears, are included in the subspecies Ursus arctos horibilis. 

Before the advent of genetic testing, subspecies classifications were based on notable physical differences between individuals from two distinct populations of the same species.  For example, a population of finches where the individuals have robust beaks suitable for cracking seeds might be considered a separate subspecies from a population of the same species that has thinner beaks more suitable for extracting insects from bark.  It was reasoned that significant physical differences between two populations translates to genetic differences between these populations, but how much physical diversity is significant enough to declare a population a subspecies?  In 1918, C. Hart Merriam divided North American brown and grizzly bears into eighty-six subspecies based on small physical differences between individuals in separate populations.  Now scientists recognize only two subspecies.

What makes the Kodiak bear so different from all other brown bears that it rates its own subspecies classification?  Probably the biggest difference between Kodiak bears and other brown bears is that Kodiak bears tend to grow larger and have bigger skulls.  According to the Boone and Crockett Club record book, the definitive record book for hunting trophies, seventeen of the twenty largest brown bear skulls taken by hunters have come from Kodiak.  Also, Kodiak bears are a geographically-isolated population, so it follows that Kodiak bears might be genetically different from all other brown bear populations.DSC_2813

This all made sense until the mid 1990’s when geneticists began studying genetic diversity across the North American range of brown bears.  Their studies showed that while there is some genetic diversity between Kodiak bears and other brown-bear populations, this diversity is probably not significant enough to warrant the designation of a separate subspecies.  In contrast, brown bears from Admiralty, Baranof, and Chichagof islands in southeastern Alaska show marked genetic differentiation from other Alaskan brown bear populations, and many researchers believe these bears should be considered a separate subspecies.

I guess all of this means that the more you know, the less you know, and there is no clear answer to why Kodiak bears are classified differently from other Alaskan brown bears.  At the present time, Kodiak bears are considered a separate subspecies, but this classification may soon change as more genetic evidence is revealed.

What do you think?  Should the classifications be changed?  Should all brown and grizzly bears be considered one species with no subspecies designations?

For much more information on Kodiak bears visit my wildlife notebook.

Dead Whales

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This summer and fall several dead whales were spotted in the Western Gulf of Alaska, with the majority clustered around Kodiak Island. The number of deaths now stands at 43 whales, including fin whales, humpbacks, and, at least, one gray whale. So far, none of the whale carcasses that could be accessed have been in good enough shape to provide a clue to the cause of the deaths, but the National Oceanic and Atmospheric Administration (NOAA) is so concerned that they have classified the deaths an “unusual mortality event” (UME). A UME is defined as a significant die-off of a marine mammal population, and such an event demands an immediate response and triggers a focused, expert investigation into the cause.
At nearly the same time dead whales were being discovered in Alaska, whales were also dying off the coast of southern Chile. In November, biologists in Chile announced that in June, 337 sei whales were found beached in a region of southern Patagonia in Chile. This is one of the largest whale strandings ever recorded. While these whales were found beached, researchers think they died at sea and washed up on the beach.
What caused the deaths of the whales in Alaska and Chile, and did they all die from the same cause? Sadly, we may never know the answers to these questions, but biologists in both Alaska and Chile suspect a harmful algae bloom may be the culprit. Most of the dead whales are baleen whales that feed low on the food chain, making them highly susceptible to a toxic algae bloom. What makes this scenario even more believable is that abnormally warm water conditions in the Pacific Ocean this summer led to a massive toxic algae bloom of the single-celled algae Pseudo-nitzschia.

Pseudo-nitzschia produces domoic acid, a powerful neurotoxin. Under normal circumstances, a domoic acid concentration of 1,000 nanograms per liter is considered high, but in mid-May, concentrations 10 to 30 times this level were found in the North Pacific. Domoic acid accumulates in zooplankton, shellfish and fish, and when mammals and birds eat these organisms, the accumulated acid overstimulates the predator’s nervous system, causing the animal to become disoriented and lethargic. Ingestion of high concentrations of domoic acid can lead to seizures and death.

In addition to Pseudo-nitzschia, the warm-ocean-water conditions in the Pacific also may have resulted in blooms of other toxic algae, but if toxic algae are the culprit, why aren’t other mammals or birds dying as a result? These are questions researchers are scrambling to answer, and recently they have been rechecking photos to see if there is any evidence that the whales may have starved to death. Warmer ocean conditions may also have led to a reduction in the prey of these huge whales that must eat nearly continuously all summer to build a large enough blubber layer to last them through the winter.

There is no time frame for when a UME must end, and biologists plan to keep researching the whale deaths for a while longer, but they admit the cause may never be known. One dead whale washed up a few miles from where we live, but we saw many other whales this summer that seemed to be feeding and acting normally, and I hope the whale deaths were an anomaly that won’t continue next spring and summer.

Next week I’ll go into more detail about toxic algae blooms. For those of you who have read my novel, Murder Over Kodiak, you may remember that Jane Marcus was studying paralytic shellfish poisoning, a condition caused by a poisonous algae bloom, and since toxic algae have been in the news this year, I think it will be an interesting topic to tackle.

I am FINALLY ready to send my first Mystery Newsletter to those who have signed up for my list. I plan to mail it on January 6th, so if you haven’t signed up for my list yet, do so soon on my home page. My first newsletter will chronicle the events of the McCarthy massacre of 1983. Thanks, and be sure to leave a comment to let me know what you think of my post!