Only the most brazen of Africa's predators will readily take on an adult hippo. These hefty herbivores – armed with 50-centimetre canines and wrapped in thick, tyre-like skin – are characteristically cantankerous and have a reputation as one of the most dangerous species on the continent. It'll take a particularly ambitious and hardy hunter to even attempt to tackle one of these 4,000-pound grumps – just the sort of challenge hyenas relish.
Captured in the dead of night on an Africam live stream in South Africa's Greater Kruger National Park, a pair of hyenas were filmed harassing a hippo that appeared to be trying to graze in peace. Hippos spend the bulk of their time submerged in the safety and coolness of rivers and dams but will emerge at night to feed. They sometimes travel up to 10km (six miles) in search of food and can consume as much as 68kg (150lb) of grass in a single night. Although you wouldn't know it from watching their lumbering gait, hippos can sprint at 18 miles per hour (29 kmph) – something they'll readily do if they find themselves stranded and separated from their watery abodes.
Hyenas are also nighttime feeders. These notorious nocturnal prowlers do much of their hunting and foraging under the cover of darkness. Widely regarded as scavengers, hyenas are actually capable hunters (the most successful in Africa – sorry, lion fans), but like all predators they will choose an easy meal if it's available. Although it's unclear how this particular interaction ended (or indeed how it began), it's likely that the hyenas realised the difficulty of the task at hand and moved on in search of easier pickings.
A hippo is an ambitious target even for hyenas and it's possible that this one may have been harbouring an injury of some kind which attracted the interest of the cackling predators. According to Luke Hunter, president of cat conservation group Panthera, surveys carried out between 1988 and 2000 in a reserve that forms part of the greater Kruger Park ecosystem identified over 4,000 kills by large carnivores. Only one of these was a hippo killed by lions, suggesting that, for the most part, this sort of prey presents too big a risk for predators.