The hyena family consists of only four species (the spotted or laughing hyena, Crocuta crocuta; the brown hyena, Hyaena brunnea; the striped hyena, Hyaena hyaena; and the aardwolf, Proteles cristata), but despite their low diversity, hyenas are vital components of most African ecosystems. Hyenas are largely nocturnal.
In 2007, 12 spotted hyenas were captured in Etosha National Park and relocated to Erindi Private Game Reserve. Four adult females were fitted with VHF tracking collars to allow the ecology team to locate them and monitor their movements. However, it was soon discovered that spotted hyenas are very intelligent and quickly learn to stay away from vehicles or people if they’re frightened by them, making it impossible to view them, and also making it almost impossible to recapture them to fit new VHF tracking collars. They’re difficult to capture in cage traps, and for a massive amount of capture effort, the team has so far managed to capture only one, very young spotted hyena. Current monitoring of Erindi’s spotted hyena population therefore involves counting through camera trap surveys and identifying
individuals from spots on strategic parts of the body.
Spotted hyenas are known to take time to settle into a new environment and start breeding, but when they finally do, their numbers can rapidly increase. This exact situation occurred at Erindi, and once clans began denning and having cubs, their numbers grew quickly. Eight years after their introduction, three of the original four founder female spotted hyenas are still thriving on the reserve and are seen regularly at different corners of Erindi. One clan has settled in the far north, one in the far south and the third in the far western sector.
This success hasn’t necessarily boded well for the spotted hyena’s cousin, however: in many game reserves in southern Africa, brown hyenas have completely disappeared, and the main reason for this has been the introduction of the spotted hyena. Spotted hyenas are the stronger of the two species, living, moving and hunting in large clans. Brown hyenas can’t compete with this sheer physical superiority, and instead have to rely on the fact that they aren’t dependent on water. Therefore, as long as there are vast areas without available water, brown hyenas will survive there, while spotted hyenas will only move through.
Erindi has put a great deal of effort into ensuring that both spotted and brown hyenas can flourish within the protection of the reserve.
To monitor brown hyena success after the spotted hyenas were introduced, the Erindi team used various methods. One was to capture brown hyenas in box traps, both to confirm their presence and to count them; certain individuals were then fitted with VHF tracking collars or VHF tracking implants, enabling them to be located daily, and providing information on their natural movements and behaviour. It was noted that their numbers did not decline with the arrival of the spotted hyenas due to the long distances between waterholes.
A number of female brown hyenas were tagged, and through telemetry tracking and monitoring, excellent data was gathered on their movements and behaviour. Den sites were located and the private life of these animals revealed. The brown hyenas on Erindi were confirmed to be ‘secretly social’, as while they moved about as single animals, they gathered in small groups at their dens. They were noted not to hunt a great deal, spending their foraging time following leopards more than any other
predator. Surveys of numbers are maintained by camera trap monitoring, and after eight years of sharing an environment with spotted hyenas and lions, the brown hyena population on Erindi is thriving.