Beavers again.

I was recently ticked off for my post on the role of beavers in the Polish floods. Scepticism was expressed about the likelihood of the floods being exacerbated by the tunnelling of beavers in the river defences. Indeed, it seems likely that the little beasts are being scapegoated for the Polish government's mismanagement of the disaster.
As a sideline to this argument we touched upon the ancient legend (it features in Aesop's Fables) that the beaver, which was hunted (among other things) for its glands, would bite off its own testicles when pursued so that the hunters, satisfied with this, would give up the chase and allow the beaver to escape with its life.  There are at least two things wrong with this tale.Firstly, the glands - which were prized for their medicinal property (they contain aspirin) were not the testicles, but the scent glands, which are situated near the anus. Secondly, the beaver's testicles are internal, so that the operation detailed in the medieval painting above would have been rather difficult to achieve.
Another matter which arises is the etymology of the verb 'to castrate' . Does this relate to the bogus behaviour of the beaver (Latin = castor)? In a word, no. According to an interesting site which I discovered, the word is related to the Latin 'castra' (a military camp) which gives so many English place manes their - cester, -chester and -caster endings.  Such fortifications were 'cut off' from their surroundings by ditches or stockades, and it is this kind of 'cutting off' that the word originally referred to.