According to fresh news, the outlook for black rhinoceroses (Diceros bicornis) has improved – unfortunately only in zoos. Although Berlin Zoological Garden (Germany) has a tradition of breeding this species and it has one of the largest breeding groups in the world, the almost concurrent birth of two calves in one zoo was still a big surprise. Can we hope for this to help achieve the goal of the European breeding programme (EEP) of this species? Let’s have a look at the background of breeding these animals in zoos.
The issue of black rhinos always reminds me of my first encounter with this species. It was when I saw a mounted head of a female black rhino that decorated the staff’s dining room, calling to mind the history of Veszprém Zoo. When I was working there, it was merely a dream for us to keep this unique species again, as the requirements and possibilities had changed. The white rhino (Ceratotherium simum) was the main and most popular species of rhinos in zoos, although their keeping system – generally only one or two animals per zoo – led to sustainability problems of the population due to a lower reproduction rate. The world has changed, and now black and Indian rhinoceros (Rhinoceros unicornis) breeding programmes seek new participants, and more support is given zoos to start with these rhinos rather than white rhinos (although last year’s tendency changed to positive direction in the case of white rhinos, too). But does this mean their situation is now rosy?
Presently, the situation of black rhinos looks hopeful, as we frequently get news about births of black rhinos both from Europe and the United States. In October our pleasure was even doubled when not one, but two babies were born in Berlin Zoo. First, Maburi had her baby on 2nd, and on 14th Kumi followed her with her calf, which is the 19th in the black rhino history of the zoo. In addition, on 11th another male rhino was born in Leipzig Zoo, also in Germany. Unfortunately this calf died of severe enteritis two weeks later.
However, the breeding of black rhinos is still a huge challenge. The number of specimens of all subspecies is about 250 worldwide, according to the Zoological Information Management System (ZIMS). The breeding programme focuses on the Eastern black rhinoceros (Diceros bicornis michaeli) in Europe, as it is a manageable subspecies due to their larger number (78 in 2014). The number of the founders of the European population was 40 (5 of them are still living). The first baby was born in 1955, and the rate of captive born animals exceeds 85% today. Thanks to the diverse and known origin of the founders and the management of the breeding, inbreeding is not significant. There is an interesting phenomenon concerning the sex ratio of captive-born babies: usually more females are born than males, which may have a positive effect on their management. The main goal of the programme is to achieve a >5% growth rate per year to ensure a healthy and sustainable zoo population. Unfortunately, the goal has not been reached in the recent years, for example, the programme needs 6 babies in 2014 in Europe, and there are still only 3... If the reproduction rate does not increase, the black rhino population won’t grow as quickly as some free living populations, which is the aim of the program - as Mr. Mark Pilgrim (Black Rhinoceros EEP) informed us.
How could the zoo community improve this programme? Dvůr Králové Zoo (Czech Republic), Port Lympne Wild Animal Park (UK), Chester Zoo (UK) and Berlin Zoo have a tradition of breeding this species, and they can share the knowledge of successful breeding with other zoos. Starter zoos – new participants in the programme – should build facilities for breeding purposes, for at least 5 animals, including both indoor and outdoor permanent separation areas which make effective management possible.
Our knowledge has expanded in this field, as black rhinos, on the contrary to white rhinoceroses, were considered a very aggressive species in the past, therefore the practice was to keep them one by one. There are many working examples of mixed exhibits with black rhinos today, and this may make this species more popular in collection planning. In addition, a husbandry guideline website is now available: www.blackrhinohusbandry.org.
Let’s return to Berlin Zoo, to the joyous events of the rhino births. The father of both babies, Jasper was born in Dvůr Králové Zoo in 1991, while Marubi, the mother of the first baby was born in Magdeburg Zoo (Germany) in 2002. Kumi, the second mother was born in Berlin in 1995. All three rhinos are captive born specimens, and the mothers are experienced, as they both had one baby in the past.
The first little bull was born at 9:30 in the morning on 2nd October, without any complications. A rhino calf usually stands up and starts to follow the mother within 11 hours after birth. This calf proved to be very viable – he accomplished his first challenging task in 4 hours.
The second bull was born at night on 14th of October, its birth weight was 35 kg (77 lb) and his length was 50 cm (1,64 ft). As Dr. Andreas Ochs, the curator of rhinos informed us, the mothers and calves were healthy and well, and when the weather is warm (above 10°C/50°F) and not rainy, the visitors can see the calves.
Unfortunately, the situation of the wild population of black rhinos is much more worrying. Their number has declined, by more than 90% since 1960, mainly as a result of poaching, according to data of the IUCN Red List. There are only about 4880 individuals left in the wild (2010), therefore the species is considered Critically Endangered. Preserving black rhinos for the future is one of the most important reasons to maintain a sustainable zoo population of these animals. Events such as the birth of these two rhino babies of Berlin Zoo, should contribute to fulfill this mission.