Well this is really true because I've observed this as well... And, I know this is about humans but...
Different animal species have their own unique "species smell", horses smell like horses do, cows smell like cows, chickens smell like chickens, fish, smell like well, fish! I'm sure you could understand too that a troop of Gorillas also has their own unique smell, and a dog smells like a dog(after a bath?)
I know it sounds weird and it's different than the subject post but it is very true and gives more credibility to this observation.
It gives me all the proof I myself need that different races of humans have their own unique smell too(but for what purpose, is it possibly something that goes understood into our minds subconsciously?) I think it plays some important roles that we do not understand....but could understand.