Study sheds light on hyenas

While it is no secret that brown hyena roam the Mountain Zebra National Park, little is known about their movement and the exact number of the current population nestled here in the Eastern Cape.

Three were released into the park in 2008, but when all three with their collars failed within 10 months, the animals faded into relative secrecy, leaving management to guess their whereabouts and how they were settling into their new home.

Camera traps set up in 11 locations throughout the park in April are now shedding light on their numbers and home ranges. While similar equipment has twice been used in the past, techniques have been fine-tuned and researchers from Rhodes University are now running a full-time, year-long study.

Lead researcher Jessica Comley says by July, they had been able to identify five animals from 37 photographs. One of these is the original male released into the park, still wearing his collar after five years.

The photos have shown hyena carrying carcasses in a westerly direction, as well as lactating females, so researchers are theorising that there is a den in the northern section of the park, possibly with cubs.

Intriguingly, they have also picked up two new animals in the south, but unfortunately, Comley also reports there are a number of photographs in which they cannot as yet be profiled.

Identification is done by the stripes on their legs, facial scars or ear notches. Their markings are asymmetrical, explains Comley, so they differ on the left and right sides.

For this reason, researchers have set up two cameras at each site to maximise their chances of capturing both sides of each passing animal. Profiles can then be developed and used throughout the sampling period, which will last one year.

The 22 remote-sensor Cuddeback Attack cameras (after the one taken by a baboon was replaced) are set across the park in grid format, according to the diameter of the male’s home range – identified as the member with the smallest home range.

Home-range data from collared animals at Kwandwe Private Game Reserve were used as a guideline, says Comley. The sites have also been mainly set up along prominent game paths or roads, as brown hyena are known to make use of these.

Another question that the researchers are trying to answer is what the hyenas are eating, and they do this by analysing the scats.
Luckily, the latrine sites have been located, so there’s no lack of evidence. Comley says prey can reliably be identified by using this method as the cuticular (outer layer) and medullary (inner layer) characteristics of prey hair are reasonably undamaged in carnivore scats and each species’ hair has its own unique characteristics.

The study results will provide park management with valuable knowledge to develop conservation and management plans. “Brown hyena is a rare species with low genetic diversity, making it highly susceptible to extinction in the wild,” says Comley.

Yet, protecting it is challenging because there is so little accurate infor-mation available about its distribution and abundance.

Understanding its eating habits is also important for management of a relatively small and fenced wildlife area like Mountain Zebra National Park, as preference for some species could have an impact on the ecology of the park.

As such, benefits from the study results could circle far beyond this national park, also providing valuable information for other closed reserves across southern Africa.