Understanding Bull Elephant Social Dynamics.
Tsavo Elephant Research, (formerly known as the Tsavo Elephant Conservation Trust) is monitoring the population dynamics of over 800 individually recognized elephants in Tsavo East National Park. Many of these known elephants have been monitored since 1989.
The current focus of the research is on Bull Social Dynamics; seasonal grouping patterns; associations between bulls and long-term bonds. The results of this research will provide insight into bull behavior and fill the gap in our knowledge of bull complex social interactions.
WildiZe provides funding for important data collection and research to better understand bull behavioral-ecology.
Project Web site: www.tsavoelephants.org
Database: sightings - location, update identification photograph, features, musth cycles and health.
Bull Grouping Patterns
Determine seasonal group size and age class distribution of all bulls (known and unknown) that are sighted alone, with other bulls or with families. Identify known bulls that associate with recognized females
Monitor seasonal behavior; feeding, water activity, resting and travel.
Determine the frequency and description of interactions among bulls in a bull group.
Analyze long-term sighting data of known bulls to determine long-term associations and bonds.
Monitor bull utilization of the habitat and natural and artificial water resources.
Monitor the impact of fires, climate change, killing for ivory, injuries from snares, fencing and livestock encroachment on elephant behavior and the environment.
In the late 1960s, there were approximately 35,000 elephants in the Tsavo ecosystem (40,000 sq. km). This population has suffered two population crashes.
The first was the drought in the early 1970s when an estimated 6,000 individuals died and over the next 4 years with low rainfall and lack of vegetation a further 3,000 died. The majority of these deaths were females and young elephants. Unlike pregnant females, females nursing a calf or young calves, independent bulls were able to travel greater distances in search of vegetation and their mortality was lower.
The second crash was due to the killing of elephants for their tusks. The large bulls who survived the drought were the first victims for their large and heavy tusks. When the remaining bulls were difficult to find, the large females were targeted (their calves died as a results) and then whole families. By the late 1980s, at the height of the ivory poaching era, about 6,000 elephants remained in the entire Tsavo ecosystem.
Aerial surveys conducted in the mid-1960 and 1970s showed that the majority of the groups sighted were confined within the National Parks. With the onset of the rains these groups dispersed, but there was little indication of large scale migrations. Before the ban on trophy hunting in 1977 elephant seasonal range was influenced by the surrounding legal hunting blocks, rainfall and the development of artificial water resources within the National Park
The study site is 4,000km² and one-third of Tsavo East National Park. The northern boundary is the Galana River. The north-western boundary contains an open-ended electrical fence, separating wildlife and humans. The Voi River flows from west to east, across the center of the study site. The majority of the southwestern boundary is not fenced off to the elephants. However the elephants that move between the National Park and private land must cross the railway tracks and the main Mombasa-Nairobi road (a dangerous route - some elephants are killed when trying to cross).
The environment within the study area is relatively flat terrain with a few hills to the northwest. The vegetation consists primarily of Acacia-Commiphora, open grassland, riverines and bushland with shattered trees.
To the north of the study area, the Tsavo and Athi River converge to create the Galana River and is typically a permanent resource. The Voi and Mbololo Rivers, which are seasonal, are important dry season riverine areas, for food and shade and an important area where elephants dig for water in the dry river bed.
The natural pools in Ashaka, Punda Malia and Sobo in the northwest a short distance to Galana River provide water for the elephants and other wildlife during the dry season.