The cool thing about science and nature is that interesting stories are all around us. The tiny Deer Mouse, shown here, has overcome long odds, with the vast majority of its historical habitat gone. However, through some remarkable, fast-track evolutionary adaptation, they’re now able to cope with their new world. Photo by Gregory Smith.
It’s been a busy last week, without any time for birding or photography. Or blogging, for that matter. I was down in Nebraska for a few days, mixing work and pleasure. The “pleasure” part was my fantasy baseball draft in Omaha Saturday. Our fantasy league is likely one of the longest running leagues in the country, going back to 1985 during our freshman year in college, when fantasy baseball was still very new. What’s great about it is that many of the original league members are still participating! It’s great fun, not only the draft itself, but catching up with old college friends.
The “work” part of my Nebraska trip was participation in the 2017 Great Plains Symposium, on the campus of the University of Nebraska-Lincoln. Much like the baseball draft, the symposium too was like stepping back in time, as I reconnected with some of my old college professors who were participating in the symposium. The focus of the symposium was “Flat Places, Deep Identities: Mapping Nebraska and the Great Plains”. I gave a talk one some of the work I’ve been doing, mapping past, present, and potential future landscapes in the Great Plains. It was a great symposium, a little different kind of crowd than I’m used to. Given the work I do, most of the conferences and symposiums I attend deal with the physical sciences. This conference melded mapping, history, socioeconomics, and other social sciences that I’m not exposed to as much. It was quite fascinating, particularly hearing about the history of Nebraska, using maps to help tell the “story” of change over time.
As part of the symposium “goodies”, participants were given a copy of The New Territory, a quarterly magazine that focuses on Missouri, Arkansas, Kansas, Nebraska, and Oklahoma. I admit I’d never heard of the publication before. The content fits quite well with the focus of the symposium itself, with many human interest stories about the geography and people of the region. As a physical scientist, one piece caught my eye though. entitled “Evolution in the Cornbelt“, by Conor Gearin. The story focuses on the Prairie Deer Mouse (Peromyscus maniculatus bairdii), a common little fellow from the Great Plains that feeds on the tiny seeds of grasses and weeds in the prairies.
Researchers at Iowa State and Purdue University were curious how a species so adapted to life in the Great Plains has been able to thrive, given that >99% of the original tallgrass prairie in the region has been plowed under, converted to agriculture, urban land, or other man-made land uses. The grass and weed seeds the Prairie Deer Mouse had historically fed on were much more sparsely distributed than they were 200 years ago, yet the species is still quite common. They started field work to assess the distribution of the nice, including setting up artificial nest boxes that the mice could use for habitation and food storage. The results astounded the scientists.
Prior to beginning the work, it was assumed that deer mice populations would be the highest in “edge” habitat, areas such as grassy ditches, fencelines, or other “boundary” conditions where remnants of their traditional food sources may still be found. However, they quickly found that the highest populations of deer mice were often right in the middle of very large corn and soybean fields, far from any traditional food source. Clearly, Prairie Deer Mice had adapted to an agricultural setting, and were feeding on man-raised grains and pulses. The question was, how could a tiny mouse that was so well adapted to eating tiny grass and weed seeds shift gears and start feeding on corn and soybeans?
The researchers found historical deer mice in historical museums, creatures that had been preserved with taxidermy. Anatomical comparisons with Prairie Deer Mice from today found some stark differences. The older specimens were well adapted to feeding on tiny seeds, with small mandibles and jaws that didn’t open very far. The modern specimens had 1) significantly longer lower mandibles, 2) structural changes that allowed their mouths to open wider, and 3) larger upper mandibles. Accompanying the larger mandibles were more robust “hardware” for linking bone to muscle, with beefed up jaw muscles that enabled the tiny mice to feed on much larger food items than they had historically.
In the blink of an eye, geologically speaking, Prairie Deer Mice had shown measurable, obvious evolutionary adaptation in response to their new environment and food sources. The researchers found high densities of deer mice in the middle of corn and soybean fields. Some inevitably will succumb to the mechanical tools humans use to turn and manipulate the soil, but with such a rich, dense, bountiful food source, the mice had quickly evolved to fill the new ecological niche and feed on corn and soybean waste.
For a scientist like myself, I’m completely dumbfounded by the sheer ignorance of those who doubt science…who doubt climate change is real…who doubt in evolution. The actual empirical evidence is overwhelming, conclusive, and “in-your-face”, for those who bother to open their eyes to the world around them. It’s a fascinating story, and the writer (Conor Gearin) did a great job not only summarizing the research, but telling it in a true story-teller’s fashion. To me, this is exactly the kind of story, and writing style, that could perhaps help to turn the tide against the anti-science wave that seems to be cresting in the U.S. right now. Great story, and The New Territory really looks like a publication that’s worth subscribing to or picking up if you get a chance.
Expansive grasslands of the Grand River National Grasslands, in Harding County, in far northwestern South Dakota. Grassland habitat like this is greatly reduced in the Great Plains. However, that doesn’t seem to be a problem for one species, the Prairie Deer Mouse, who evidently can do quite well without an actual “prairie”.
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