Studying Large Carnivores with GPS Technology: Spotted Hyena Research Project
From the annual report submitted to the Government of Botswana by The Botswana Predator Conservation Program (Dr. J. W. “Tico” McNutt, Director)
In this project monitoring five clans of spotted hyenas known to be resident in an area of the southern part of Moremi Game Reserve and the adjacent Wildlife Management Areas, four of the five clans are monitored and identified (Table 1) through GPS collars. Four individuals in three clans (Athena, Ceres and Poseidon) are fitted with GPS radio collars, and two females in clan Ginger are fitted with a traditional VHF radio collar. Collaring of additional hyenas including at least one male and one female in the fifth clan is planned for the first semester of 2008.
|Clan||Adults + sub-ad||Cubs|
Table 1. Four spotted hyena clans currently in the large predator guild research project.
In contrast to traditional VHF radio collars, GPS radio collars can be set to record an animal’s location at any time without an observer being present, providing us with the unique opportunity to remotely follow animals on a fine spatial and temporal scale. By the end of September, individuals of all five large carnivore species that occur in northern Botswana have been fitted with GPS radio collars, including five lions (Panthera leo), three leopards (Panthera pardus), two cheetahs (Acinonyx jubatus), four spotted hyenas (Crocuta crocuta), and one African wild dog (Lycaon pictus).
Location data from spotted hyenas fitted with GPS radio collars earlier this year show an interesting difference in home range size according to habitat type (Fig. 1). Clan Ceres and Clan Athena almost exclusively inhabit grassland habitat or former flood plains associated with Acacia woodland. The range of Clan Poseidon falls almost entirely within mopane woodland, which supports comparatively low prey density. Clan sizes and memberships are still being determined, but our analysis suggests that the density of spotted hyenas is likely to vary widely depending on habitat type and associated prey availability in northern Botswana.
GPS radio collars are also equipped with two bidirectional motion sensors (accelerometers) that record an animal’s activity continuously at five-minute intervals. Interestingly, activity data from spotted hyenas show that males are considerably more active than females: 10 hours versus 7.5 hours of activity per day.
Figure 1. Home ranges of three neighbouring clans of spotted hyenas in northern Botswana (Moremi Game Reserve and adjacent Wildlife Management Areas): clan Ceres in red, clan Athena in blue and clan Poseidon in green. Note the interesting loop that Ceres (orange dots) made around clan Athena’s home range within 48 hours. Recording this kind of movement patterns is only possible with GPS technology.