connection between Castor (one of the Διόσκουροι) and the animal (beaver)?

Question

The history of the Ancient Greek word κάστωρ (beaver) is unclear. It may be :

• a foreign loan-word (? Sanskrit कस्तूरी kastūrī, “musk”)
• a Greek word meaning "shining (animal)" from καίνυμαι (perfect κέκασμαι)

Latin castōr (a beaver) is nothing but a loan-word from the Greek.

There's no evidence that Κάστωρ (the proper name) and κάστωρ (the beaver) have a different origin. But as far as I know, nothing in the legend of the Διόσκουροι deal with a beaver, or with a specific animal.

Is there a connection between both names ?

Answer 1

The currently favoured view is that (late) Sanskrit kastūrī- is a loan from Greek, not the other way around. There is no consensus about the origin of κάστωρ “beaver” or its relationship with the name Kάστωρ. The connection with the verb "to shine" is however surely a folk etymology.

Beekes writes: “Schrader-Nehring 1917: 138 point out that the animal no longer existed in Greece; the word would be foreign. It is first mentioned in H[ero]d[o]t[us] 4, 109 in the North Pontic area, which is close to the supposed homeland of the Indo-Europeans, so the word could in principle be inherited.”

I would regard this as a hypothesis rather than as a fact.

Answer 2

I am simply quoting etymonline.com which has the following under "castor":

"It has been assumed that the hero's name was given to the animal because he was a noted healer and the odorous reddish-brown secretions of the inguinal sacs of the animal (Latin castoreum), were used medicinally in ancient times, especially for women's diseases. But the animal did not live in Greece in classical times (the closest beavers were north of the Black Sea), and the name probably was borrowed from another language, perhaps influenced by the hero's name. The Greek word replaced the native Latin word for "beaver" (fiber)."