Question: what are the black bits in my dogs fur?
Answer: Spotting the Culprits Black specks on your dog or in your dog's bed may be “flea dirt” – the fecal matter from adult fleas. There are two easy ways to check for black specks: Run a flea comb over your dog, making sure the comb reaches the skin through the coat. ... If black specks appear on the towel, it may be flea dirt.