I am currently reading The Bear: History of a Fallen King by Michel Pastoureau. It is a history of the bear as a symbol and as a living creature in Europe, especially medieval Europe.
Pastoureau describes how medieval intellectuals classified and described the European brown bear. It was deeply controversial to even contemplate that any animal was related to man, as this conflicted with the belief that man and man alone was made in the image of God. Nonetheless, some people considered three possible animals to be close to humanity: the monkey, the pig and the bear. Pastoureau writes:
For Aristotle and Pliny, the monkey was the closest to humans. This idea found support in some zoological learning in the High Middle Ages, but it considerably troubled Christian values, not only because man had been created in the image of God and any animal of any species was an imperfect creature that could not resemble him, but also because, for medieval sensibilities, the monkey no doubt represented everything that was most ugly, vile, and diabolical; it was an obscene and repugnant creature that it was impossible to associate with the human species [...] Scholasticism finally found a solution in the mid-thirteenth century; the monkey did not resemble man per naturam (by nature) but per imitationem (by imitation); it seemed to resemble man when it really did not resemble him at all. It "simulated," as the word for monkey in Latin indicated: simius. It therefore seemed even more demonic, because it tricked and deceived. [...]
Greek medicine considered the pig the animal closest to man because of its internal organization, notably with regard to the anatomy of the major organs and functioning of the digestive system [...] And medieval Christian medicine, the heir of both, also taught that the pig was "internally" the animal that most resembled man. Moreover, since the Church prohibited the dissection of the human body, at least up to the fourteenth century, human anatomy was often learned through the dissection of a sow or a boar. But that was not done without some reluctance: the pig was in no way an admirable animal. It was an impure creature, an emblem of dirtiness (sorditas) and gluttony (gula), sometimes of laziness (pigritia) and debauchery (luxuria); like the monkey, it found a place in the Devil's bestiary. This is why, although doctors knew that the pig was anatomically a cousin to man, they did not declare the fact too openly and allow clerics to assert that the animal that most resembled humans was neither the pig nor the monkey, but the bear (60-61).
Bears can stand up, grasp and throw objects, climb and dance. When they walk, they plant their entire foot on the ground. Bears are omnivorous. At least one medieval intellectual (William of Auvergne) claimed that bear meat tastes like human flesh. There were also widespread (but inaccurate) beliefs that ursine sexual practices resemble human sexual practices and that humans and bears are interfertile.
Image via Got Medieval