Yep, coyotes have been known to attack humans and their dogs. Here's a famous example but it happens from time to time to ordinary mortals like thee and me.
http://www.cnn.com/2009/SHOWBIZ/Music/10/29/canada.singer.killed/More:
http://www.info.com/search?qkw=coyote+attack&qcat=webTwo dozen and more years ago, there used to be a shoot-on-sight attitude, and a bounty on their tails or pairs of ears in Colorado. But with increasing ubanization and encroachment on their habitat, and no hunting or varminting allowed in or near cities, they're just about everywhere nowadays. (Sometimes those bounties ($25-$50, a lot of money in those days) were privately-offered by farmers and ranchers, sometimes by the County Extension Agents, sometimes both.)
I live in a transitioning area, with pastures on three sides of my building, and just about every evening one or more coyotes can be seen crossing the pasture south of me. One late afternoon one was crossing the pasture carrying some kind of prey and a magpie started to harass it. I got a picture of that activity, but it was so far away that it is hard to tell what was happening just from the pic. Attached is a cropped version of a wide angle pic I took. The coyote was about 150 yards away, and you can just barely make out the magpie in the air to the right of the coyote. Past the fence in the background there is a river, and past that, some suburban homes. The coyote finally took off running with its prey and the magpie flew off. This picture was taken in haste, and I was just about 30 feet from my car in my parking lot. I did not have a chance to fool around with the camera settings and zoom and all that stuff.
There is probably at least one mountain lion hereabouts, too, but mountain lions are pretty sneaky and stealthy. There was a report of one by an elementary school nearby, and I'm pretty sure I found some tracks in the snow out by my car --like a big dog print, but with no claws showing.
I'm kind of a nightowl, and when I go out to take my trash at, say, 3AM, I've always got a flashlight and a gun on me and sometimes a knife. I wave the flashlight around the pasture looking for pairs of retinal reflections. However, according to what I read of the very rare actual attacks, lions attack at dawn-ish and dusk-ish. Actually, in that kind of encounter, a knife would probably be more effective if one got through my hail of panic-stricken inaccurate wild shots.
I do hear screams of animals all the time, and although it doesn't happen that often, I hear gunshots as well. A lot of these semi-rural folks keep animals like goats and llamas and of course horses in this transitional zoning.
Every once in a while I get the notion to pull out my varmint call and go out there and sit in my car and start calling just to see what comes up. But that varmint call would be sure to result in my neighbors calling the cops from all the squawking. Sample:
(That's not me, but it might as well be, since that's exactly how I looked when I went varminting, right down to the rifle and the long hair. I used a .243.)
I've got a funny story about my own varmint calling, but that'll wait for another time.
Terry