In 2008, some scientists proposed that cows can sense magnetism and actually line up in fields along Earth's magnetic lines. It's the sort of paper that everybody in the media wants to talk about for, roughly, two weeks … and then never mention again.
But that's not how science works. One research paper does not an unquestionable fact make. Luckily Discover's Discoblog has been kind enough to update us on the current state of magnetic cow research. Shorter version: This issue is far from settled, with a second research team attempting to poke holes in the original study. Nevertheless, outside researchers say, the original findings still look strong. There is evidence that herds of cows stand along magnetic lines, and fail to stand along those lines in the presence of magnetic-field distorting high-voltage power lines. Whether this is absolutely the case and, if so, why, remains a bit of a mystery. Needs moar research.
… an analysis of Google Earth images by another team finds no such lining up. In a back-and-forth over the last year in scientific journals, the first team reanalyzed the second's data and said that half of the images were useless, since they were near high-voltage power lines or contained hay bales or sheep instead of cows. Plus, the first team points out that the second team looked at single cows within herds instead of herds as a whole, and it's pretty clear at this point that animals in herds and flocks aren't operating as independent entities. The second team retorts that their images were too okay to use, and the first team may have been looking at the wrong pictures.
Image: Cows, a Creative Commons Attribution (2.0) image from 35463710@N06's photostream