Black Bear. Once near extinction (in the mid 19th century) and then reintroduced in the middle of the 20th century they are now managed. In some areas of the Ozarks, their existence is quite rare and in other areas they're considered a game animal. While you won't see them on every hike or outing, if you're lucky, quiet and careful ... you just might. If you do, be smart and safe ... keep your distance and never, ever feed a bear!
Mountain Lion. Also known as cougar, puma and panther. They are rather rare within the Ozark region, but they have been spotted. As with most large predators in North America, man's existence had helped to eradicate them to the point of extinction. Primarily to protect life and limb (not to mention livestock). Today, modest conservation projects help to monitor and protect their numbers in the wild, but generally not in this region.
Through encroachment and hunting all other beasts of size are gone. Almost all animals of size such as the plains bison, wolves, caribou, moose, mountain lions, elk and black bears were nearly wiped out by the early to mid 1800's. Today, only the elk survive in abundance and the true dominant mammal of size (based on population) is the white-tailed deer.
Related Reading (off-site)
More Images of Beasts
Ozark White-tailed Deer