Now parts that excrete things, butts, genitalia and the mouth, I can understand. But why would an armpit, a foot, and say a guys uh, “coinpurse” have different odors? Yeah, they all have differing functions, and I would presume differing types of sweat glands and such, but isn’t odor caused by bacteria? Are there armpit bacteria, and foot bacteria that just like it there more than the other place?
Perspiration odor is caused by bacteria, but I don’t that is true of all odors. There are all kinds of oils and stuff. Sweat from stress tends to give off more odor than sweat to cool the body (I think this may be related to its hospitability to bacteria). Hormones has an effect on what comes out. The feet are closed up in socks and shoes all day and can foster growth of bacteria and fungus not at home elsewhere.
Different parts of the body are colonised by different types of bacteria:
Human skin teems with a zoo of strange microbes in colonies that are nearly unique from person to person and many of which are practically unknown to science, new research finds. Some of the bugs are permanent residents, while others come and go.