Saturday, April 10, 2010

A Tale of Two Whales – I Won’t Know It When I See It

Because you have seen something doesn’t mean you can explain it. Differing interpretations will always abound, even when good minds come to bear. The kernel of indisputable information is a dot in space; interpretations grow out of the desire to make this point a line, to give it a direction.
~ Barry Lopez, Arctic Dreams: Imagination and Desire in a Northern Landscape (1986)

This posting is about the tension between the observed and the explained, particularly for the paleontology amateur.

On April 16, 1982, writer Barry Lopez was aboard a plane flying over the Bering Sea when he and the others on board the plane sighted two narwhals in the ice filled waters. These whales are literally fantastic, so striking in their appearance and so shrouded in the mythology of unicorns because males typically grow long, single lance-like tusks that stick out from their heads. According to Lopez, to witness living specimens of this specific species in the Bering Sea was a stunning biological event, unprecedented in the annals of science. (The narwhals pictured below are off West Greenland, not in the Bering Sea. This photo is from the National Oceanic and Atmospheric Administration, courtesy of Mads Peter Heide-Jørgensen, link here.)

The narwhals’ presence at that place was the “something” that Lopez wrote one might see but not necessarily explain. Explanations, he asserted, involve interpretations, and, ultimately, interpretations invoke agendas, either held by the interpreter or someone acting on the interpretation. As a result, the myriad possible uses to which an explanation might be put “make good scientists chary.” At the time he wrote, oil exploration was on the horizon for the area and the presence of narwhals might constitute a “complicating environmental nuisance” to those companies holding oil leases, seriously raising the stakes for any scientist choosing to give meaning to the sighting of the whales. As Lopez posited, good scientists “are sometimes reluctant to elaborate on what they saw, because they cannot say what it means, and they are suspicious of those who say they know.”

I am bound up in that tension. For many years, I worked for an organization whose primary asset was a reputation for impartiality – all of our written work went through the “Joe Friday filter” (“All we want are the facts, ma’am.”). I chafed at suppressing my natural inclination to interpret, to ascribe meaning. That’s what human beings do . . . no, not chafe, . . . look for meaning. Besides, the goal was a chimera, even the very selection of which “facts” to report and in what order moves the writer across the line. To take it to its logical conclusion, even the selection of the topic itself is laden with meaning. Lopez’s scientists knew that; “[s]ome even distrust the motives behind the questions.”

But, my dilemma in the realm of amateur paleontology is even more fundamental than challenging the asking of the question. Honestly, I would love to get into the mess of explaining or interpreting, but I often get stuck on the observation. It’s not because there is anything at all at stake in an explanation that I might attach, it’s because I literally don’t know the what of what I see. Lopez wrote about the “kernel of indisputable information,” but what is that? I suppose it’s where we reach common agreement, a starting point – I saw that happen or I saw that object. Not so easy when I rely on my untrained eye.

Here is a for instance.

On a raw March afternoon on the western Chesapeake Bay, I knew I had company on the beach though no one was in sight. It required no sixth sense to realize I was not alone, footprints marred the shoreline and the faint, pungent smell of cigarette smoke corrupted the air. In disgust, I dropped to my knees and began to crawl along the furthest reach of the murky waves, looking for what little might have escaped detection so far today, looking for what would take some work to discover. I turned over small stones. I reached under and behind smallish chunks of gray, clayey slump from the cliffs. The cliffs abutting the shore were composed of the fossil-rich Calvert Formation, deposited during the lower and lower-middle Miocene. (Slump is a nicely expressive geological term used to describe the movement downhill of a fairly unified mass of rock debris and soil, as well as to describe the material itself that moved en masse.)

Bone. There was lots of fossil bone on the beach. Clearly, some slab of cliffside replete with bone had fallen at some point in the last several days and been broken apart in the surf. My fingers found a long, tapered object nestled against the base of a rounded piece of the slump. What was it? A piece of bone? A tooth? I slipped it into a pouch for safe keeping. Once home, I soaked it clean and photographed it. (The composite photo shows either end of the specimen.)

At what point could this event of mine become a kernel of indisputable information? For Lopez, there was no doubt that what he and the scientists observed were narwhals in a place they were completely unexpected. As simple as it was, there was a high level of specificity and knowledge built into the statement he could immediately make that day above the Bering Sea.

In contrast, here’s what I could say that day on the Chesapeake Bay shoreline – “I found this long pointy thing among the float material.”

Frustrating. The difference? Education, training, experience, and the company of experts.

So, I worked hard at generating a kernel of indisputable information about my find. It was a challenge because, once you get beyond the sharks and shark relatives among marine vertebrates, you’ve left the world of good, comprehensive, accessible guides, printed or online. I found a lead in the material I had in my small library which suggested I had a tooth from a whale. I turned to the primary literature that might be available online, aided, in part, by the very useful Biodiversity Heritage Library (where digital versions of some of the old literature reside), as well as the Paleobiology Database (where taxonomic information can be found on fossil specimens of plants and animals). Nevertheless, without access to the resources of a large research university library, you have to be very lucky to find copies of all of the most relevant material. Further, when that literature lacks pictures or drawings clearly resembling what you have in hand, even finding that literature doesn’t solve the basic dilemma.

That’s when other eyes need to be brought into the effort. So, I showed the specimen to other amateur paleontologists who didn’t hesitate in their identification (ah, there’s the experience at work). And, finally, I sent pictures to a professional paleontologist along with my tentative identification, one that he promptly and graciously confirmed (he was bringing to bear extensive experience coupled with education and training).

What I found is a tooth from an extinct sperm whale, an Orycterocetus crocodilinus. According to Michael D. Gottfried et al. (Miocene Cetaceans of the Chesapeake Group, Proceedings of the San Diego Society of Natural History, 1994, Volume 29, pages 229-238 – available in the Biodiversity Heritage Library), the O. crocodilinus was the largest toothed whale or, for that matter, the largest cetacean found in the Calvert Formation, but only one of many different genera and species of cetaceans found in this formation. (I’m easily distracted by the little things – this whale had teeth in both its lower and upper jaws. In contrast, extant sperm whales apparently only have teeth in their lower jaws which fit into empty sockets in the upper jaws. Amazing.)

Okay, here then is my kernel of indisputable information – “I found the tooth of an extinct sperm whale, an Orycterocetus crocodilinus, on a beach on the western side of the Chesapeake Bay at the foot of a cliff composed of Calvert Formation material.”


I guess there’s nothing to explain about that, no interpretation to apply, because the larger meaning – that the O. crocodilinus inhabited the waters of the Salisbury Embayment when it covered this area during the early portion of the Miocene – is accepted. The still larger question of why it and the rest of the rich assemblage of odontoceti (toothed whales) lived in waters there when the Calvert Formation was being laid down is another story for which there is no consensus explanation (and, to which, I suppose, this fossil has nothing to offer).

End of story. Well, I also found this piece of bone on the beach the same afternoon (see picture below). On the left is the exterior of the specimen, on the right, the interior.

Note the two deep slash marks on what is apparently the outside of this bone fragment. Perhaps, because there is nothing at stake and this fossil begs for an explanation, I can be excused for moving from seeing to explaining, even if I cannot create that kernel of indisputable information, because I cannot identify with any certainty the origin of the bone or the source of those marks. It clearly helps to be able to involve someone else in an explanation, well, more than just involve. I’ll put it in someone else’s words while I’m at it. Gottfried et al. wrote:

One well-substantiated aspect of Chesapeake Group cetacean paleobiology is that both mysticetes [baleen whales] and odontocetes were preyed upon and/or scavenged by sharks. Cetacean bones regularly show linear grooves and gouges caused by shark bites during attacks and/or scavenging on carcasses.

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