The Latest in Marathon One-Upmanship: Have You Ever Run From a Rhino?

ENTABENI SAFARI CONSERVANCY, South Africa—In the pink post-dawn light, nearly 300 runners stretched and limbered up, some nervously chattering, some focusing silently on the task ahead—running 26.2 miles in a game reserve filled with the five most-difficult African species to hunt: rhinoceros, leopard, buffalo, elephant and lion.

“Guys, when you see a ranger with a rifle, that means that something could be quite close by,” J.P. Meyer, the jovial and khaki-clad general manager at Honeyguide Ranger Camp, said during a briefing the day before the 12th running of the Big Five Marathon in June. “If our rangers do tell you, ‘Please, get on the vehicle,’ there’s a reason for it. Something brown and furry is joining the marathon.”