The critically endangered black rhinoceros (Diceros bicornis) is described in most texts as being a generally solitary, anti-social and to not maintain any long term stable bonds. Though they are certainly not herd animals, long term monitoring of known individuals in large (+100 individuals) free ranging populations in Zimbabwe suggests that black rhinos maintain strong social bonds for many years, even decades. Over twenty years of tracking and sighting records document reoccurring interactions between specific individuals – not just breeding females with breeding bulls or cows with dependant calves. Neighbouring breeding females have been recorded to maintain intermittent contact with each other. Newly independent calves may spend extended periods of time in the company of a familiar neighbour. Dominant bulls have been recorded spending extended companionable time with young bulls (likely to be their sons).
The difficulty in learning more about how frequently these interactions occur is that black rhinos are predominantly active at night and this is when the majority of their interactions occur. Trying to follow and observe black rhinos at night directly presents challenges as black rhinos often do live up to their reputation of being irascible. Another particular challenge with black rhinos is their neck shape does not lend itself to conventional GPS collaring as the bulky neck pushes the collar forward against the soft tissue of the ear base and significant lesions can develop rapidly. There are GPS units designed to be inserted in the horn but presently this technology is still quite bulky such that these devices can only be fitted into adult bull black rhino horns.
Black rhino bull with two non-breeding age females
Mataki devices have the promise of being able to overcome these challenges. The devices are small enough to be implanted in the horns of female and sub-adult black rhinos, allowing us to gather data on a larger demographic than just adult bulls. The Mataki also has the potential to transmit data between tagged animals – so when two (or more) Mataki tagged black rhinos come together, this event is recorded by the devices. The Mataki device can then pass this information on master tags which are placed at water-points through the rhinos home range. The data is then recovered from these tags without disturbing the black rhinos.
Better information on the social behaviour of black rhinos will contribute not only to our understanding of the species but also to better inform how we manage them. Moving black rhinos to establish new or reinforce existing populations is a critical component of this species recovery but all too often newly introduced rhinos are killed or badly injured in intraspecific fighting. It is possible that with greater appreciation of black rhinos social nature we could better avoid such problems.
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