Until recently, giraffes have been relatively understudied. No longer the “forgotten megafauna” new research is rapidly filling the void, uncovering a fascinating ecology. Such data are vital, as many subspecies of giraffe are in decline. The reticulated giraffe (Giraffa camelopardalis reticulata), inhabiting northern East Africa, have fallen in number from perhaps 30,000 a decade ago to about 5,000 today.
Domestic camels (Camelus dromedarius) are increasing in stocking levels in Laikipia, Kenya due to their ability to resist drought, and premium milk prices. Stocked in the traditional pastoralist fashion, little work has been done how domestic camel herds interact and impact their environment. This study gathered data on the foraging ecology of camels and giraffe at a Laikipian ranch to try to understand whether there are indicators of overlap in resource utilization. Two-minute group scans of giraffe and camels were used to record feeding heights and plant species. Feeding height categories were ground-truthed by measuring animals (camel) or observed browsed vegetation (giraffe). In addition to observations, a sample of female camels wore GPS collars, while giraffe encounters were recorded on GPS, and photos taken for pattern identification. Vegetative structure and density were recorded using transects along animal browsing trajectories.
Results/Conclusions
Female camels actively browse from ground level up to 3 meters, while giraffe range spans 1.1 - 4.8m. Camels browsed most intensively between 0.7-1.5m, while giraffe at 2.4m. However, giraffe showed sexual dichotomy, with males browsing most often between 3.6 - 4.8m, and females most frequently between 1.1 - 2.1m. Excluding grasses and forbs, camels browsed on 9 plant species, with Acacia brevispica being the most frequent. Giraffe ate 8 plant species, most often Acacia mellifera. Feeding heights corresponded to vegetative structure, but giraffe do not feed at the highest neck extent given the opportunity. Camels are constrained in where they browse by their herders, but covered 8km with daily browsing orbits radiating up to 2.2km from the boma.
Camels overlap most frequently in feeding heights with female giraffe, and feed on seven of the same species. These results show that camels utilize similar habitat and will overlap with giraffe for resources. Such overlap could impact plant health, current browse availability for giraffe, as well as the ability of juvenile plants to grow into the giraffe’s optimal feeding height range. The degree of overlap is ultimately dictated by the boma site selection, husbandry, and herding practices of the camel owners.