Wednesday, September 24, 2008
There is no more obvious face of American environmental problems than the cow. In the name of cattle production the American farmer has damned up streams to create livestock watering opportunities, ripped out native grasses to plant brome and fescue, plowed under wetlands and riparian lands to plant alfalfa and hay, and concentrated them into a location so densely that rainwater becomes lethally toxic. Cattle production (or maybe just farming in general) is probably directly responsible for more species becoming extinct than any other human activity in North America.
But that doesn't mean the cow itself isn't a fascinating animal with a cool story. The scientific name of the cow is Bos primigenius (at least, that's my understanding...there's some taxonomy confusion here), and it was first domesticated back in the 6th millenia BC in Mesopotamia. The original animal is known now as the Aurochs and holy god is it a cool animal. Aurochs once roamed basically all of Europe and Asia, and were independently domesticated at least 3 times. This is particularly amazing if you read the following account by Caesar about the aurochs in Germany:
Gallic War Chapter 6.28, "...those animals which are called uri. These are a little below the elephant in size, and of the appearance, color, and shape of a bull. Their strength and speed are extraordinary; they spare neither man nor wild beast which they have espied. These the Germans take with much pains in pits and kill them. The young men harden themselves with this exercise, and practice themselves in this sort of hunting, and those who have slain the greatest number of them, having produced the horns in public, to serve as evidence, receive great praise. But not even when taken very young can they be rendered familiar to men and tamed. "
I've never seen much written about animals using domestication as a life-history strategy, but this is one species where it has obviously been an advantage. The domesticated aurochs (i.e., cattle) began wiping out the wild aurochs almost immediately. Humans found cattle to be incredibly useful animals: You can hitch your wagon to one to pull things, you can feed it grass and it will produce milk, and killing even a single adult will give you enough food for months. As a result, humans agressively aided the expansion of cattle at the expense of aurochs. The last known aurochs lived in Poland and were 'protected' by royal decree. Nevertheless, the last individual died in 1627 and its skull currently resides at the Livrustkammaren in Stockholm. Two brothers, Heinz and Lutz Heck, had the bright idea of recreating the aurochs back in the 1920s (oddly enough, as part of a Nazi propoganda campaign). Theoretically, this might be possible if all the original genes are still around, you would just need to combine them. The results of these efforts are the Heck cattle, and man, you need to look into this yourself, because there is no end to the awesome (see awesome picture below).
Modern cattle have been developed into distinctive breeds for different purposes. In the United States, a federal grading standard in 1927 somewhat stupidly lead to meat quality becoming associated with 'marbling', and so breeds like Angus and Hereford have been the ideal. Marbling was considered important primarily because it made farmers more money. Marbling happens because grass fed cattle are 'finished' on a grain-heavy diet. In particular, a guy named Alvin H. Sanders, editor of Breeder's Gazette, promoted this idea so strongly that it caught on with the Department of Agriculture. The stated purpose was to promote meat that was of high quality culinarily, but as it turns out, marbling contributes relatively little to the overall tenderness of cooked meat. The U.S. eventually altered the grading system to lessen the importance of marbling, but is still one of only three countries in the world that grade beef on fat content (Japan and Korea are the others).
Cattle are generally slaughtered between 15 and 24 months in the U.S. (usually closer to 2 years), while in Europe the slaughtering times vary with the culinary traditions (Italians: 16-18 months; 3-4 years in France and England prior to prion diseases). Generally these variations have to do with the toughness of the meat and the flavor, although a lot of both has been sacrificed on the alter of efficiency. For instance, most culinary applications value the flavor of grass-fed beef, yet in the U.S. the economies of scale and a traditional over-abundance of cheap corn have resulted in massive feedlots where cattle are raised for 4-8 months on grain instead of grass.
I've never eaten veal and I can't honestly say I see the appeal. Veal is essentially beef that tastes and feels nothing like beef. The longer an animal uses its muscles, the tougher and more colored the meat becomes. Veal are usually confined so they can't move and slaughtered before ever given a chance to eat solid foods. The result is meat that is pale, extremely tender, and delicate in flavor. My feeling is that if you want to eat pork, just eat pork!
Because cattle are so closely associated with humans, there is ton more information out there: Their relationship to other ungulates, the amazing amount of fish kills that they caused prior to the clean water act, and their impact on rangeland birds are all interesting topics. However, I just got back from vacation and this is all I'm going to write today.
Tuesday, September 16, 2008
Both striped and spotted skunks have a long history as important furbearers. From the 1920s-1930s the spotted skunk was the third most harvested species in the Kansas fur-trade, averaging around 100,000 pelts a year (a level apparently believed to be sustainable), which was 3rd behind the striped skunk and possums (Roy 1997). The skunk appears to be a historic resident of Kansas, and most of the Great Plains, but some authors (e.g., Choate et al. 1973) have speculated that other spotted skunk species (i.e., the western Spotted Skunk, S. gracilis) may account for sightings prior to the agricultural settling of Kansas. In general these accounts refer to the spotted skunk as common throughout the state, even more common than striped skunks in some areas, up until about the early 1940s (Nilz and Fink 2008).
The late 30s/early 40s saw the number of skunk pelts declining significantly. By 1977 the season on these skunks was permanently closed and in 1982 the species was listed as threatened by KDWP. This wasn’t a uniquely Kansas phenomenon. Declines also occurred throughout the lower Midwest (Arkansas, Iowa, Missouri, Nebraska, Oklahoma; summarized in Nilz and Fink 2008) and potentially elsewhere in the species’ range (Reed and Kennedy 2000).
The skunk feeds on all kinds of small mammals, arthropods, birds and plant matter and is generally considered an opportunistic omnivore that benefits agriculture by eating rodents. There’s been some suggestions that the skunk moved west with agriculture and attained high densities only when benefiting from old, relatively wasteful, agricultural practices. The advent of modern farming, with less waste, chemical methods to control pests (rodents) and less ‘fringe’ habitats seems to correspond to the decline of the species. As a result, modern agricultural practices are generally considered to be at the heart of the skunk’s decline.
And decline is the right word. The spotted skunk’s preferred habitat is…just about anything native. According to the available data (which is admittedly scarce), the skunk does well in woodlands, prairies, riparian areas, scrub-land, and around abandoned farmhouses. Yet despite the huge range of habitats and food options available to the skunk, it’s almost totally absent from the Kansas landscape. Almost all the recent data comes from road kills and trappers. Nilz and Fink (2008) summarized the recent data and demonstrated that the distribution of the known occurrences of this species has continued to decline in the last thirty years. Almost nobody I’ve ever met has even seen one.
There’s a lot more out there to talk about, for instance, quite a bit is known about the evolutionary origins of this species. And apparently the skunks are in the same family as ‘stink badgers’, which I’d never known even existed. Unfortunately, I’m out of time for this week.
Choate, J.R., E.D. Fleharty, and R.J. Little. 1973. Status of the spotted skunk, Spilogale putorius, in Kansas. Transactions of the Kansas Academy of Science 76:226-233.
Johnson, C.E. 1921. The “hand-stand” habit of the spotted skunk. Journal of Mammology 2:87-89.
Kinlaw, A. 1995. Spilogale putorius. Mammalian Species 511:1-7.
Nilz, S.K. and E.J. Finck. 2008. Proposed recovery plan for the Eastern Spotted Skunk (Spilogale putorius) in Kansas. KDWP.
Reed, A.W. and M.L. Kennedy. 2000. Conservation status of the Eastern Spotted Skunk Spilogale putorius in the Appalachian Mountains of Tennessee. American Midland Naturalist 144:133-138.
Roy, C.C. 1997. 1995-1996 Kansas furbearer surveys and investigations project summary. Kansas Department of Wildlife and Parks, Unpublished report, 70 pp.
Verts, B.J., N. Leslie, and A. Kinlaw. 2001. Spilogale gracilis. Mammalian Species: 674:1-10.
Thursday, September 11, 2008
Wednesday, September 10, 2008
Lampreys are a fairly unique class of aquatic vertebrates with an apparently ancient lineage. Every description I’ve read identifies them as superficially similar looking to eels, but lacking a jaw and instead having a round, sucking disk mouth (Cross and Collins 1995, Wikipedia, the Great Lakes Fishery Commission, etc.). That is to say that they are elongated, have no scales, and have spine-less fins. However, the resemblance is pretty much completely superficial. In fact, lampreys are not even true fish (Cross and Collins 1995, Tree of Life), and in 2006 researchers found a fossilized lamprey that was virtually indistinguishable from the modern animal (article about the find) from 360 million years ago. That is way back there, when fish were just evolving jaws.
Lamprey life-history is fairly straightforward...for an amphibian (which it isn’t). The larvae are called ammocoetes, and live in mucky sediments consuming microorganisms (at one point, it was thought these were a totally different species). After 5-7 years of this, they grow eyes and a new mouth, get bigger and learn how to swim. Then they spent ~18 months swimming around and sucking the blood out of fish large enough for them to latch onto (this varies tremendously by species, Chestnut lampreys, the Kansas Threatened species I’m gradually getting to, do not survive more than a year and are adults only a very short amount of this time). Adults then move upstream into smaller streams and reproduce. Reproduction occurs by spawning (egg and sperm release) into shallow, excavated depressions in gravel beds, and the hatched offspring move downstream and spend much of their lifespan in the benthos.
Lampreys are typically thought of as blood-suckers. Indeed, many of the most well-known members of this are fish parasites that kill their host and cause untold economic damage. The introduction of sea lampreys into the
With all that context, why is there a lamprey species listed as a Threatened species in
Hall and Moore (1954) also described the Chestnut Lamprey’s ecology and habits in
These days, the species if found in
G.E. Hall and G.A. Moore. 1954.