Young Southern white rhinos may produce four distinct, context-dependent calls
Small sample of calves also suggests call development might be innate
March 7, 2018
Young Southern white rhinos may produce four distinct calls in differing behavioral contexts, according to a study published March 7, 2018 in the open-access journal PLOS ONE by Sabrina Linn and Marina Scheumann from the University of Veterinary Medicine Hannover and Serengeti-Park Hodenhagen, Germany, and colleagues.
Describing species’ vocal repertoires can provide insights into how they communicate. Little is known about how young Southern white rhinos vocalize, and how their calls compare to those of adult rhinos. The authors of the present study characterized vocalizations in a small sample of rhino calves, aged between one month and four years old, at three zoos in Germany. They used audio and video to record the calls of seven calves reared by their mothers as well as one hand-reared calf.
The researchers found that the calves produced four distinct call types: “Whine”, “Snort”, “Threat”, and “Pant”. The call rate of Whines, which appeared to indicate an intention to suckle, decreased with age. Snort, Threat and Pant calls were used in differing social interactions with the mother, other rhinos and zookeepers, and have previously been described in adult rhinos. The hand-reared calf produced all four call types in similar behavioral contexts to the mother-reared calves, which might indicate that the calls have a strong innate component rather than being learnt from mother rhinos.
These observations were drawn from a sample of just eight young rhinos in captivity, and might not generalize to calves in the wild. Nonetheless, the authors state that their findings provide the first evidence that young white rhinos may produce specific context-dependent call types. They note that the semi-social lifestyle of white rhinos, where juveniles remain close to their mothers for several years, might lead to increased vocal communication compared to other solitary rhino species.
“Our study provides first systematic data on vocal communication of infant and juvenile white rhinoceros and first evidence that there is a strong innate component to the development of vocal usage and production in white rhinoceros”, says Sabrina Linn.
Northern White Rhinos (NWR) are functionally extinct, as only two females of this species are left on the planet. An international team of scientists has now successfully created hybrid embryos from Southern White Rhino (SWR) eggs and NWR sperm using assisted reproduction techniques (ART). This is the first, ever reported, generation of blastocysts (a pre-implantation embryos) of rhinos in a test tube: here.
There are only two northern white rhinos left worldwide, both of them female. Saving this representative of megafauna from extinction seems impossible under these circumstances, yet an international consortium of scientists and conservationists just completed a procedure that could enable assisted reproduction techniques to do just that. On August 22, 2019, a team of veterinarians successfully harvested eggs from the two females who live in Ol Pejeta Conservancy in Kenya — a procedure that has never been attempted in northern white rhinos before. The eggs will now be artificially inseminated with frozen sperm from a northern white rhino bull, and in the near future the embryo will be transferred to a southern white rhino surrogate mother. The successful procedure was a joint effort by the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) Berlin, Avantea, Dvur Kralove Zoo, Ol Pejeta Conservancy and the Kenya Wildlife Service (KWS): here.