What is the differences between castor gras and castor sec?

Well Castor gras and castor sec were made by the aboriginals. They trapped beaver and used their fur to make these. Well castor gras is a fur coat (made from beaver skin) they put the smooth, downy underfur against the skin and used the coarse side of the fur was on the outside. while it was worn it became somewhat greasy... The french thought that this was more important and valuable. castor sec is pretty much the same thing ecxept it was left to sit for a few seasons, then then the fur wasnt good, it was all dry so it had to be scraped off, soaked in water and crushed to make a material like thick, wet cardboard. this was considered less valuable to the french becauseit was not ready to be used.

Hope this helped. Sincerely Panther99

I looked at a link to McGill re this question. Castor gras beaver skins were worn by natives for about a year. The friction wore down the long sharp 'guard' hairs and became soft and smooth & were prized in England for hats and coats. The castor sec were dried skins and were called parchment skins in England & Europe, they were not as valuable.