Unicorns: Finding & Befriending

I don't have all the unicorn data, but here's what I've read and experienced.

You have a hidden "Wildlife" skill that can get up to level 6.  Your easiest way to level this is (I'm guessing) finding the Wild Horses and hanging out with them.  Make them your friends.

After petting maybe 3 deer and befriending 2 wild horses on my Sim, I ran into a unicorn.  He appeared in a shower of rainbow sparkles in the middle of the wild horse herd at around midnight (they seem to congregate at public fishing spots, i.e. Appaloosa County Water Treatment), and when I went into Map View, a big old rainbow cloud hovered over that lot while showering (you guessed it) sparkles.  So, when a unicorn appears, apparently it's really easy to spot on your map.

See?  Easy!

My wildlife skill was apparently high enough that he's willing to hang out with me (I've read that it needs to be at 6, but I don't know how high mine is/was).  Once you're Best Friends, you'll get an "Invite Unicorn to Join Household" option.  :)

"Be my unicorn?"

"Sure!"

Named him Shadow Dancer.

Only complaint is that I wish you could tell the gender of wild/stray animals before you adopt them.