This pair is a thick and shiny black fur of unknown origin. Tag just states leather. I would guess either a rabbit or Chinchilla by the length is not short but not like a shaggy and its so soft and shiny. There is no signs of wear on these boots as you can see on the sole there seems to be nothing to show wear. They are not including original box so cannot promise someone didn't wear these on carpet lightly but seem to be unworn.
Sized EU 37 which should be a US 6. 5 but online inch to shoe size puts these larger SO YOU NEED TO use measurements for fit. I take these on outer boot bottom sole with back of boot firm against the wall and measure to center toe and also with soft tape from heel to toe. I have additional measurement photos if you like to see. I always suggest finding a comfortable like shoe or boot and compare the outside measurements. I sell a LOT of footwear and my clients always complement about the accurate fit if they follow these suggestions.
I have provided some photos of measurement also.
MEASUREMENTS:
Heel to toe - 10. 5 inches
Width widest part - 3. 75 inches
12" inches tall
Calf is approximate at between 14" to 15"

This item is sold from an excellent, highly rated vintage boutique in Beautiful Eastern Wa.