@bombuzz@qikipedia That was my first thought. Humans, wanting to separate themselves from anything instinctual or "animal," use scented products to cover up natural scents, some of which are sending information, to some people who are willing to read it.
@qikipedia That has been among English riddles for centuries, but the wording I saw (already old, and I'm old :-) ), had nice alliteration in the second line:
Those we caught, we threw away;
Those we couldn't catch, we kept.