Of course we mated with your brown furry creatures and that is how, eventually, your people came to be. For you to arrive as you are now, took successive generations and ages of time...for us it has been a brief interlude, just a breath in and out, a dalliance and then we travel on, no regrets. Endless amusement. On to the next flirtation, seduction and passage of our genetic materials.
This is what we do.
We chose the furry creatures out of consensus, more or less. Some of us were taken with the underwater behemoths so there are some errant strains, but they didn't go too far. The pleasures of warm skin covered with soft and bristly hairs, energetic muscles and gripping skeletal structures were not to be denied. There was a frenzy of coupling at first, then a quieter more sensual time, and now only the occasional meeting, fraught with nostalgia. Oh those moonlit nights when we were new!
It is time for us to go soon.
You are beginning to ask questions. You have identified a missing link.