The Kruger park has a fair number of hyena clans and they are quite visible most of the time. It is fairly common to see a hyena or even a few traversing the bush looking for food. They are quite skittish creatures though incurably curious as well. They are not so much disturbed by the vehicles as they are curious about them and often times will come right up to the cars.
This is especially true at the den sites. There are culverts under the roads to help rain water pass under the road and it is in these that hyena dens and also wild dog dens are often found. In the dry season they are commonly used and in the wet season naturally they are used when the water has already drained past.
The exciting thing about the den sites is you get to see hyena cubs. These are the most adorable looking creatures and their large, dangerous mother also is somewhat softened by their presence, though there is no doubt what would happen if you ventured too close. Some mothers have seen it all and know the cars pose no harm and are quite relaxed as the cubs and young ones frolic around the vehicles.
Of course they might chew a piece off the car but that is the risk you take while getting close up to hyenas. They have the strongest jaws among land predators and one of them took the tow bar cover off my car and ate it! Ha!
