PROPOSED MOVE OF NORTHERN WHITE RHINOS FROM CAPTIVITY TO AFRICA 

Background

Northern white rhinos (NWRs) formerly ranged over parts of north-western Uganda, southern Chad, south-western Sudan, the eastern part of Central African Republic, and north-eastern Democratic Republic of the Congo (DRC).  Devastated by poaching, only about 30 animals remained in DRC’s Garamba National Park by 1995.  Garamba suffered from repeated incursions from the janjaweed militia and now the Lord’s Resistance Army.  Manageable, containable subsistence poaching in the Park for bushmeat was replaced by full-scale poaching for rhino horn and elephant ivory.  In 2005, a planned emergency translocation of five NWR from Garamba National Park to a sanctuary in Kenya became ensnared by political and local and national divisions and subsequently was cancelled.  The only signs of possibly four NWRs were seen in August 2005, but the likelihood of any animals remaining now is improbable.  In 2008, some of the world’s best rhino trackers were unable to confirm the existence of NWRs in the Park.  There are now eight NWRs remaining, all in zoos.

The International Rhino Foundation (IRF) began intensive involvement with NWR conservation in 1995, investing several million dollars in an attempt to save the subspecies.  After intensive engagement in Garamba National Park for more than a decade, the deteriorating operational and rhino status in the area, combined with exhausted financial resources, compelled the IRF to close its program there in 2005. 

The Remaining NWR Population

The current NWR population is held in two institutions, the San Diego Zoo’s Wild Animal Park (SDZWAP) and ZOO Dvůr Králové in the Czech Republic.  Southern white rhinos (SWRs) have reproduced reasonably well through natural mating in captivity.  Only recently has artificial insemination (AI) been successful in rhinoceroses, resulting in three SWR births in Hungarian and Spanish zoos.  The Leibniz Institute for Zoo and Wildlife Research (IZW Berlin) reproductive experts have attempted AI with the NWRs in ZOO Dvůr Králové but no pregnancies resulted. 

The Current Discussion

In 2002, Raoul du Toit (WWF-SARPO) and a handful of others advocated outcrossing NWR with SWR as a last ditch effort to salvage valuable genetic material.  In May 2004, Dr. Tom Foose (IRF Program Director until his death in May 2006) coordinated responses to this suggestion – which were not seriously considered at that time by the key players engaged in the current discussions.  Unfortunately, this idea has resurfaced at a time when the window for success is closing and may well be closed.  The IRF and SRI deeply respect the good intentions of all the parties involved and recognize that all stakeholders are making valid and important points about conserving the NWR.

The IRF, SRI, and most parties agree:

• Wild populations of NWR are likely extinct in DRC and the Sudan
• The remaining eight individuals in captivity are not reproductively ideal
• Steps to preserve genetic material from the captive population are needed immediately
• Crossing NWR with SWR is the only remaining option

However, the IRF and SRI do not endorse the concept that the only way to succeed with this effort is to move the remaining animals to Africa. 

The information presented in the widely-distributed document ‘Our last chance to save the rarest large mammal on Earth’ (August 2009) is misleading, referring several times to a breeding nucleus of NWR that just needs to move to ‘the green, green grass’ of Africa to be saved, capitalizing on the ‘romance’ of idea rather than the real on-the-ground conservation needs for rhinos.  The Memorandum of Understanding among the parties involved in the NWR Conservation Project (ZOO Dvůr Králové, Ol Pejeta Conservancy, Back to Africa, and Flora and Fauna International) states that all parties will assist in raising funds for the project and that lists of individuals targeted for donations of $10,000 and above will be shared between the signatories.  We interpret this to mean that the effort will not be funded by one or two large donors who might not normally fund in situ conservation efforts but rather funding will be sought from many smaller donors with an existing interest in this kind of work.  The IRF and SRI and other conservation organizations or donors that routinely support in situ rhino conservation have already been approached for funds to support the move of the remaining NWR from ZOO Dvůr Králové to Africa.  IRF and SRI have declined to support the project in part because we cannot justify diverting funds away from other critically endangered rhino species and populations that actually still have a chance to be saved. 

Further, the August 2009 document outlines only the first year costs for the project, leaving the question as to how annual recurring costs for the project involving these long-lived animals will be funded. 

Considerations and Recommendations

Preserving genes must be the highest priority.  Unquestionably the most important action for the remaining NWR is to quickly preserve existing genes.  Sperm samples from all available males need to be appropriately collected and cryopreserved, and male and female cell lines should be immediately established.  Frozen and/or fresh sperm from NWR should be utilized in SWR females without delay in an attempt to produce subspecies ’hybrid’ offspring.  However, even if such practices are successful, it must be recognized that the current population is so small, the reproductive viability of extant animals is so uncertain and the generation interval is so long that the odds of success are remote. 

Are benefits realistic compared to the risk to the animals?  The rationale behind the proposed move of the remaining NWRs to Africa is that a ‘natural’ environment might somehow trigger reproduction.  However, as outlined in the table above, all but one of the ZOO Dvůr Králové NWR are advanced in age.  There is no evidence in any species that reproduction can be stimulated in aged animals.  Further, if it were true that translocation could somehow stimulate reproductive success in older animals, then this effect could be accomplished by any move (i.e., even within their current geographic area).  Regardless of destination, there is a real risk of older animals dying during an extended transport. 

Female reproductive pathologies are not likely to be resolved by a move to Africa.  Perhaps most importantly, examination of all of the females (including the one born in 2000) by the IZW Berlin specialists have revealed varying degrees of serious reproductive tract pathologies.  Zoo experience with rhinos suggests that the longer a female goes without breeding, the more likely she is to develop reproductive problems.  Although not as severe as the older females, the 9-year-old female already is demonstrating reproductive abnormalities.  Again, there is no biological rationale or expectation that moving animals to Africa will reduce the type of pathologies described by the IZW team.  Drs. Robert Hermes and Thomas Hildebrandt are among the world’s foremost reproductive experts and have produced SWR offspring by AI.  Although they have not yet been successful in similar studies with the NWR, we believe it would be more cost effective and safer for these specialists to devote more study to the existing NWR population, especially if the animals are moved ‘locally’ to provide more outdoor space and a warmer climate.  This would allow intensive monitoring via behavior, hormonal assessments and ultrasound in a more controlled environment – and collection of valuable scientific data.  The latter opportunity will not be as readily available if the animals are returned to Africa and released as proposed.  Further, we recommend that females be given the chance to naturally mate with SWR males as much as possible. 

Is moving just the males a more viable option?  Moving the two ZOO Dvůr Králové males to breed with SWR females seems to us a less risky and more viable tactic, but one which does not seem to have been considered to-date.  We advocate this approach, especially to a facility that has available significant numbers of SWR females as mates or as recipients for AI.  If significant SWR females are available in Africa (in a captive or wild situation), we would be supportive of that move.  However, if it is believed that AI will be necessary, then these males (and others that are still producing sperm) should be moved to a facility where reproductive specialists can focus on semen collection and cryopreservation.  Banked sperm from the male at the SDZWAP should also be considered for this endeavor.  Given the solid status and population numbers of SWR, then we recommend identifying females of the latter species as ‘experimental’ for producing the hybrid calves.  Further, we support this concept even if the NWR might potentially pass on the Robertsonian chromosomal abnormality to progeny. 

Security and disease issues.  We do not believe that security or disease risk issues should hinder efforts at this time.  Ol Pejeta and Lewa Wildlife Conservancy both have excellent records of rhino protection.  Some veterinarians have raised concern about Babesia being a disease issue which could affect the translocated animals.  In partnership with Cornell University, IRF recently had success adapting cattle vaccine for Anaplasma and Babesia to help protect a US zoo-born Sumatran rhino prior to transport to Indonesia, and that protocol could be used with the NWRs.  The captive animals can easily be checked for any disease risk they may pose to the wild population and we believe this issue that can be dealt with fairly quickly.  Richard Kock and colleagues[1]  suggest that SWR may be highly susceptible to trypanosomosis caused by T. brucei which is prevalent in East Africa but not South Africa.  SWRs appear to be reasonably tolerant to local trypanosome species in southern Africa.  Kock et al. suggest this perhaps is not surprising and there is no indication that reducing the infection challenge will lead to resistance as translocated animals have died some months after controlled exposure in Kenya.  We cannot predict how the NWR will respond to similar challenges, but believe this may be an acceptable risk given the severity of the situation.

What is the ultimate goal?  Finally, and most importantly, all stakeholders advocating the saving of NWR genes by hybridizing with the SWR must clarify the ultimate goals.  Even if it was possible to overcome these major reproductive hurdles, it never will be possible through species mixing and then backcrossing to produce the original NWR.  Our best hope is to salvage some of the critical genes that have allowed the NWR to adapt to ecosystems in its historic range. 

Conclusion

IRF and SRI do not wish to obstruct or delay action on the captive NWRs, but rather to see a decision that involves the best possible animal management, science and technology available.  Our most profound concern is that the current debate over these four NWRs is diverting valuable time, energy and potential away from field sites and wild rhinos in desperate need of assistance.  The real crisis facing African rhinos is that systematic poaching is decimating populations at rates approaching the 15-year high that led to the demise of the NWR wild population in the first place. This should be our collective focus, and it remains the paramount objective of both the International Rhino Foundation and Save the Rhino International. 

Thank you very much for your consideration.  Please do not hesitate to contact either of us if you would like further information.

Sincerely,

Susie Ellis, Ph.D.      
Executive Director      
International Rhino Foundation    International

Cathy Dean
Director
Save the Rhino