Gerlache Strait

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While many people will continue, for various reasons, to call the above animals “orcas,” I prefer to use the term “killer whale.”

First, it sounds rad. These whales ARE killer, man!

Second, it’s pretty out of the norm for a species* to be referred to by the second part of its two-part name (Orcinus orca, in this case- the first half is genus and the second half is the species designator). You’d never talk about “sapiens” and expect people to understand you meant “humans;” if you referred to “musculus” and expected me to know what animal you were talking about, I’d have to guess if you meant a blue whale (Balaenoptera musculus), or a house mouse (Mus musculus).

Third, and most importantly, I follow the opinion of scientists that I respect greatly in thinking that there’s no way that all of the different types of killer whales across the globe (oh yeah, they’re everywhere, in every ocean, doing their killer thing) are still one species. Just in the Antarctic, there are at least five types of distinguishable killer whales, each of which has a population separate from the others, probably with their own social structure, language, and feeding habits (further study needed). In the Pacific Northwest, where I did a week or two of research with Holly Fearnbach and John Durban (NOAA scientists and generally awesome human beings), three types of killer whales co-habitate but never interact, studiously avoiding contact while passing each other in a narrow strait, consuming different food sources, speaking different languages… Maybe it hasn’t been long enough in evolutionary time (hundreds of thousands of years) for them to have genetically diverged enough to make reproduction between groups impossible, but unless they’re forced (in captivity, for example…), different types of killer whales will never interbreed. In some cases, they’d have to cross continents to do so.

Anyways, these are the “small Type Bs,” also known as “Gerlache Strait killer whales.” They feed (probably) on deep-dwelling toothfish and other large predatory fish in the Antarctic, and are significantly smaller than the “large Type Bs,” which feed on seals. You can see in the photo their yellowish tinge- type Bs and Cs both have diatom (algae) coatings on their skin, which they travel north to shed- and the “cape” of grey around their backs. They can be distinguished from the large Bs by size, and from the Cs by the orientation and shape of their eye patches, and overall can be identified by their presence in their namesake, the Gerlache Strait. Aren’t they beautiful?

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