On Wed, 25 Dec 2013 14:13:10 -0500, jmcquown
I know from reading about cats all black and grey cats are basically brown.
I just gave Persia a nice brushing. She's not a long-haired cat but she
still has a nice ruff around her neck. Well, I noticed it's turning
brown. Same thing with her chest.
I cannot capture this in a photo, sorry. It is rather surprising.
Tyrosine deficiency? This site is interesting;
And it points to this one which seems more definitive: