I have a friend from church that bow hunts large and sometimes dangerous game. He has hunted bears in the past, but says there is not much challenge to a bear. All they are is a stomach that has big teeth. Elk (which didn't make your list) are far more difficult to hunt. American Bison are very tough skinned, but bow hunters do pretty good on them too. In talking with hunters that do the Africa big 5, they say Texas Longhorn Cattle are a good and tough choice. They can get on the nasty side when in the thick scrub brush. Ivan