What is it?

I was listening to a commercial the other day about dust, pollen and dander and thought, "hey! just what is dander?" I've heard the word many times through the years and haven't stopped and said what is it? That's crazy to hear something and never wonder what it means, but it's said so frequently that it never registered. Pretty bad, but I finally decided to look it up. I asked Sher and she knew right away. Guess my brain needs exercising. Anyway here it is:

Dander: Etymology: alteration of dandruff1 : DANDRUFF; specifically : minute scales from hair, feathers, or skin that may be allergenic

"Don't get your dander up".....! Here's another explanation http://www.phrases.org.uk/bulletin_board/5/messages/289.html

GET YOUR DANDER UP - "Many of the early Yankee humorists - Seba Smith, Charles Davis, Thomas Haliburton - used this Americanism for 'to get angry,' and it is found in the 'Life of Davy Crockett.' It is one of those expressions with a handful of plausible explanations. The most amusing is that the dander in the phrase is an English dialect form of 'dandruff' that was used in the Victorian era; someone with his dander up, according to this theory, would be wrathfully tearing up his hair by the fistful, dandruff flying in the process. Another likely source is the West Indian 'dander,' for a ferment used in the preparation of molasses, which would suggest a rising ferment of anger. The Dutch 'donder,' 'thunder,' has also been nominated, for it is used in the Dutch phrase 'op donderon, 'to burst into a sudden rage,' And then there is the farfetched theory that 'dander' is a telescoped form of 'damned anger.' And if these aren't enough, we have the possibility that 'dander' comes from an English dialect word for 'anger,'; from the Scots 'danders,' for 'hot embers'; and from the Romany 'dander, 'to bite.'" From "Encyclopedia of Word and Phrase Origins" by Robert Hendrickson (Facts on File, New York, 1997).