One of the enduring myths in molecular physics, when talking about chirality as pertains the existence of enantiomers and the differences between them, is that the way cows chew is also chiral, i.e. the up-and-down and the around-in-a-plane movements combine in such a way that you can distinguish a cow chewing from its mirror image. This is mentioned in e.g. Wikipedia, among other resources.
A recent question in the Physics site asked for the source of this factoid, which turns out to be
Movements of the Lower Jaw of Cattle during Mastication. P. Jordan and R. de L. Kronig. Nature 120, 809 (1927),
and this is a rather unsatisfactory source: they report on a survey that finds that 55% of cows chew in a 'right-circular' fashion and 45% chew left-circularly, but they then go on to disavow any statistical significance in the result:
The number of observations was, however, scarcely sufficient to make sure if the deviation [in the ratio of the two kinds] from unity is real.
Given that this isn't a physics question, I thought I'd bounce it over to the mammalian behaviourologists out there: have there been further studies about which way cows chew? I imagine that they're out there, but I wasn't able to find them.