The traditional focuses of sociology include social stratification, social class, social mobility, religion, secularization, law, sexuality and deviance.
These were called calceus mulleus, and the name may have been shortened to mules by English speakers. Hence the primary difference between mules and clogs in early days was that clogs were likely to be worn by working people, and mules were fancier and favored by the aristocracy.
The body and barrel, however, of the hinny are flat and narrow, in which it differs from the horse and resembles the she ass. The difference between the mule and the hinny would seem to be explicable on this supposition. The mule is the progeny of the male ass and the mare; the hinny that of the horse and the she ass.