Wonderful - thank you

. Is there no end to enjoyable Tolkien reading? Just as I'd reduced my 'still to-read' pile of Tolkien criticism under the coffee table to just one book

.
Back to Beorn.
The Ring of Words: Gilliver, Marshall and Weiner (dig out your copies, Merry and Mabreterese) has a section on 'bee-hunter and skin-changer':
Bear bee-hunter, boar the fighter
The line comes from Treebeard's roll of living creatures.....
The key can be found in R.W. Chambers' Beowulf: An Introduction (third edition, 1963). Chambers observes (p.365) that the obvious interpretation of the name Beowulf is 'wolf (or foe) of the bee.' Many who have accepted this interpretation nevertheless could not see a reason for the hero to have this name, but Chambers asserts that 'bee-foe' simply means 'bear': 'The bear has got a name, or nickname, in many northern languages from his habit of raiding the hives for honey.' That Tolkien had assimilated this idea is clear from the Elvish word for bear, megli, which is a compound word meaning 'honey-eater'. The bear, in the legends of Scandinavia, Finnish, Sami (Lapp) and Slavonic peoples, is regarded with awe and thought to have human understanding and enormous strength; hence 'bear' is an excellent name for an epic hero. '" bee-hunter"' writes Chambers, 'is then a satisfactory explanation for Beowulf.' (Chambers' book was forst published in 1921; Tolkien's own lecture on 'Beowulf: the Monsters and the Critics' was given in 1936, when The Hobbit was in the making.
Chambers' also points out that the Old Norse for 'bear', bjorn (which is ultimately realated to 'bear') seems to have an exact cognate in the Old English word beorn. In Old English, this word meant not 'bear' but 'warrior, a hero, a man of valour............ the entymological ambivalence of Beorn's name is translated by Tolkien into narrative, for at night Beorn the mighty man changes his shape from human form to that of a huge black, bear. Another allusion to the legendary background lies in the beehives which surround Beorn's hall and the honey which he mostly lives on.
They also come up with this quote from Gandalf that answers Lyanness's question. Beorn is a
black bear

:
'[Beorn] is a skin-changer: sometimes he is a huge black bear, sometimes he is a great strong black-haired man'
Gandalf - The Hobbit
They also talk about skin-changers, saying the diversity of Beorn's name reflects what he is - a skin-changer and quote Gordon's
Introduction to Old Norse:
In the extract, Gordon explains the origin of the Old Norse word berserkr (from which English beserk is derived): 'Beserks were probably named "bear-shirts" from a superstition that they were "skin-changers"'. Gordon also says that a beserkr was a 'wild warrior on whom a fighting-rage descended like madness' and that it was probably believed that 'they got superhuman strength from their animal nature.' This accords well with Beorn's spectacular wrath at the Battle of the Five Armies.
Gawd - that was a lot of typing

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What huge knowledge and riches Tolkien has hidden in a single name!
See what an interesting conversation you've sparked off with your questions, Lyanness?