As some people above noted, he is in graduate school studying anthropology. Every bit of mainstream anthropology follows the Franz Boas doctrine that race does not exist.      This is what he believes. Partially true, I am sure, but they refuse to admit that race can exist.     I've brought up the dog breeds etc, he agrees with that but sends me biased articles by Jews (with little to no research, oddly enough...I make sure of these things) that are well known scientists in their anthropology or biology fields stating that DNA shows that we are all very similarly related.  I have sent him articles back saying we are similarly related but not too much. I have also sent him much on the differences in race and intelligence, mostly supplied by the book The Bell Curve.   Most of this communist version of anthropology is made from the assumption that race does not exist. So based on this, you have to prove to them race exists first. Try not to concentrate on dogs alone, there are many other species check the majority rights link.    How can he explain bone marrow incompatibility in mestizos? if race doesn't exists like he says....