Reconstructing Prehistoric Behavior & Ecology of Northern Fur Seals

As an undergraduate, I was one of the lucky ones. I was part of some ground breaking archaeological research. Between 2002-2004 I spent roughly the last years of time as a student in anthropology working with Dr. Diane Gifford-Gonzalez on a zooarchaeology project. She was my mentor then, and kinda still is now.

I was employed as a lab tech under her grant. The grant funded research that focused on assessing what the hell happened to the Northern Fur Seals (Callorhinus ursinus) Male Northern Fur Seal, <em>Callorhinus ursinus</em>.which once inhabited the Monterey Bay area. Specifically, we worked on a archaeological site right next to Moss Landing Marine Labs. At this job, my primary role was to identify bones and bone fragments. It was hard work and involved a lot of creativity and a strong background in osteology and comparative anatomy.

Reconstructing a species, let alone an ecological community based upon hundreds of tiny bone fragments is challenging. Often I had to employ logical shortcuts, for example marine mammals have more dense bones than their terrestrial counterparts. So if I had a bone in front of me that was more dense than the rest, but not quite complete to tell what it was — at least I had something to narrow down the scope, it was most likely a marine mammal.

Working on faunal identification from bones for a couple years, I noticed that there was once a lot of Northern Fur Seals there. I don’t quite remember the minimum number of fur seals we estimated, but it was staggering. And nowadays, if you have ever been to Moss Landing there are about umm zero Northern Fur Seals… except maybe the one or two that wash up dead from exhaustion, starvation, and/or shark or killer whale attacks. What was even more remarkable was that I saw the evidence that humans where the ones that killed off the Northern Fur Seals.

See bone is a pretty remarkable medium, not only does it help organisms move around and function. It caries a lot of information about life history. Diet and nutrition reflects a lot on bone robusticity and chemistry. Any traumatic event, such as a fracture, persists on bone for millenia. Above all, any processing such as butchering done on bone, by humans, gives one a big clue about what happen, who was eating what, and what sort of behaviors can we infer from the ways these humans hunted and processed these animals.

Time and time again, I saw Northern Fur Seals with bashed in skulls, indicating me that whoever hunted these animals clubbed them. We found a few spear points and other stone tools. But in general, these people didn’t waste resources, such as spears nor arrows, on them… and that made sense. There’s no reason to spear an animal that can’t really run away, may as well use brute force. Pretty extreme hunters. These seals were most likely killed on the beach front where they usually bask and have rookeries.

The animals were then dragged out about a half mile away, at the Moss Landing Marine Lab site, to be cut up and processed perhaps at a temporary village. Long bones, such as femur, have traces of cut marks, which tell me the meat was removed there and the bones with rest of the carcass was thrown off into a midden pile. Some of the bones were charred black, telling me that some people feasted on the animals right there and then. Whoever they were, they were hungry about 1,000 years ago.

After graduation, I no longer could be supported by the educational grant. I moved off to the big bad world. I hadn’t heard on what was happening with this project since then, until now. I was checking my regular anthro-blogs, and noticed a headline from Afarensis that caught my eye. He titled his blog post, “Archaeology and Northern Fur Seals” and as I read his description of the research it sounded awfully familiar.

Low and behold, Diane, my adviser and mentor, had just published a paper on the results of this project in PNAS. She collaborated with a lot of other people who brought in biochemical and ecological evidence. The paper has been published under this title, “The shifting baseline of northern fur seal ecology in the northeast Pacific Ocean,” and here is the abstract,

“Historical data provide a baseline against which to judge the significance of recent ecological shifts and guide conservation strategies, especially for species decimated by pre-20th century harvesting. Northern fur seals (NFS; Callorhinus ursinus) are a common pinniped species in archaeological sites from southern California to the Aleutian Islands, yet today they breed almost exclusively on offshore islands at high latitudes. Harvest profiles from archaeological sites contain many unweaned pups, confirming the presence of temperate-latitude breeding colonies in California, the Pacific Northwest, and the eastern Aleutian Islands. Isotopic results suggest that prehistoric NFS fed offshore across their entire range, that California populations were distinct from populations to the north, and that populations breeding at temperate latitudes in the past used a different reproductive strategy than modern populations. The extinction of temperate-latitude breeding populations was asynchronous geographically. In southern California, the Pacific Northwest, and the eastern Aleutians, NFS remained abundant in the archaeological record up to the historical period ~200 years B.P.; thus their regional collapse is plausibly attributed to historical hunting or some other anthropogenic ecosystem disturbance. In contrast, NFS populations in central and northern California collapsed at ~800 years B.P., long before European contact. The relative roles of human hunting versus climatic factors in explaining this ecological shift are unclear, as more paleoclimate information is needed from the coastal zone.”

If heavy handed science writing ain’t your thing… you maybe interested in reading the official press release about this publication from my alma matter.

Aside from the research experience I gained at this position, I learned a lot about forming intelligent conclusions and behaviors from archaeological material. In this situation, the abundance of fur seal bones indicates that people exploit food sources to extinction in times of need no matter who they are and what sort of cultural background they come from.

4 thoughts on “Reconstructing Prehistoric Behavior & Ecology of Northern Fur Seals

  1. … and the bones with rest of the carcass was thrown off into a mitten pile.

    I guess it’s no surprise that Northern Fur Seal hide makes good mittens, but why throw bones onto the mitten pile? It’s mysteries like these that make anthropology interesting I guess…

    Wonderful article nonetheless.

  2. Wooops, Hewelly… I meant to write midden not mitten! Hahah, big mistake… gotta correct that. But I am sure the fur was used for warmth, there is evidence that fur seal pelts were used for trade all the way up in Mt. Diablo and Emeryville, California.

  3. Afarensis, I will do my best to email it to you tomorrow afternoon. Off-campus access to my library is broken right now.

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