In the forested areas you can find raccoons, bobcats, deer, cougars and even bears. Again ... most of them would just as soon leave you alone as mess with you but, it's definitely a good idea to keep little kids under a watchful eye. The biggest problem is small animals like little dogs and cats .. coyotes will get them and that can happen in very populated areas, I live on Centerville Rd and Waterloo and we have had coyotes at our back fence. I don't let my little dogs out alone.
Also, we have had hawks get our chickens and go after our small dogs. No danger to your kids of course but do mind your pets.
I live in an area where we have seen bear & bobcat and cougars have been seen by others. We have deer and raccoons in our yard on a regular basis. Our greatest risk however probably comes from insects.
Large animal on human attacks are very rare and make big news when the happen. Reasonable precautions are to make noise if you enter a wooded area and don't leave attractants around your property like birdseed or pet food.
My kids play in the 5 acres of woods behind our house and I rarely give it a second thought.