Press Release - 13th August 2012
August 13 2012

Review of Hunter et al. paper “Walking with lions: why there is no role for captive-origin lions Panthera leo in species restoration“

Early in 2012 ALERT was presented with a first version of the above mentioned paper that purported to present an evaluation of the African Lion Rehabilitation & Release into the Wild Program.  This was to be achieved despite none of the authors having visited the program, included direct attacks on individuals working for ALERT and was factually inaccurate throughout.  Needless to say the paper was not published following an initial peer review.  A much revised, more general, version has now been published online and ALERT has commissioned an independent peer review to assess the validity of the opinions given.  We present here the findings of that review.  As an overall statement, we feel that the article, while published in a scientific journal, is no more than an opinion piece.  (The journal-published version of this statement - Attending to the ‘biological, technical, financial and sociological factors’ of lion conservation: a response to Hunter et al. can be downloaded here)

Hunter et al. (2012) seeks to dismiss the need for captive-origin lion restoration programmes.  These are rendered as nothing more than commercial tourist attractions adding little to the conservation of the species.  In contrast, the authors promote the merits of wild-born lion translocation programmes as sound conservational operations.  Unfortunately, the paper fails to marshal a range of evidence to assess either type of species restoration initiative satisfactorily.  Rather, the paper delves into an unsubstantiated attack on captive-origin programmes, labelling them as “failures” without recourse to evidence to warrant such claims, nor evaluating the steps involved in such programs to alleviate the suggested failures.  It is a shame that in order to endorse wild translocations, the authors feel they must scorn alternative conservation operations, with arguments based on conjecture rather than scientific fact. 

Hunter et al. begin their attack on captive-born reintroduction operations by noting some actual ‘failed’ reintroduction attempts (lynx and jaguar) and two proposed programmes (tiger and leopard).  Two inter-related things are immediately striking here.  Firstly, none of these reintroduction programmes concern lions, and secondly none of them concern large social felids.  So, to assume captive-origin lion reintroduction programmes are ‘failures’ based on these previous and proposed attempts is speculative in the extreme.  These are not equivalent operations.  We simply do not have evidence that lion reintroduction programmes, using captive-origin lions are, or will be, failures.  Indeed, initial evidence from the release of a captive-bred pride of lions is very encouraging with the lions becoming self-sustaining and successfully raising cubs, meeting the established criteria for success for this stage of the program.  We should also consider that past failure is no reason not to try again with a fresh approach, whilst dismissing a program that can enhance the toolkit of available conservation solutions shows little foresight of where the African lion could well be in a few years time.  

Ngamo release pride

Secondly, it becomes clear in the paper that one particular organisation is unfairly taken to be representative of captive-origin reintroduction programmes; to suggest that ALERT is representative of the many cub-petting or lion-walking operations that exist around Africa is specious. Certain judgements are made of how ALERT operates, but crucially the paper makes the point that neither ALERT, nor other operations, address the reasons for the decline of lions in situ without mentioning or evaluating ALERT’s approach and efforts in tackling these important issues.  


The authors claim that reintroduction efforts are “ad hoc”.  On what basis is such an assertion made?  Where is the evidence for this?  Have they examined the procedures in place in these programmes (and ALERT’s in particular) and found them wanting?  If so, they need to present their data and conclusions from such examinations. 

Interestingly, the authors note that carnivore reintroductions are “profoundly limited by biological, technical, financial and sociological factors”.  Unquestioningly, these are fundamental issues which need to be addressed and the decline in lion populations and the possible solutions for this are complex and nuanced.   But, how do the authors know these factors have not been, and are not currently being, addressed?  Moreover, surely these issues are also relevant to wild-origin lion translocations.  How have they been addressed in these kinds of operations?  There are points in the current paper where deliberation of these factors seems to be absent from explanations of wild-translocation operations.  Surely it would be a stronger argument to explain how these factors have been addressed in wild-origin lion operations than to simply assume captive-origin reintroduction programmes have failed to do so.  For example, if wild-born lions are being translocated to an area where numbers have either become vulnerably low, or the population has been wiped out, what measures have been taken to ensure the same reasons for the original loss do not reoccur?  Has there been an identification of the issues that led to declining numbers in the first place and have these been effectively tackled before moving more lions in?  Anthropogenic factors accounted for all post-release deaths of founders in the case of a reintroduction of lions to Phinda in South Africa, where five lions died in snares and three lions were euthanized after killing a tourist (Hunter et al., 2007).  A recent case includes the death in a snare of one of four lions translocated to Liuwa Plains National Park in Zambia (African Parks 2012).  

This brings us to the issue concerning disease. As the authors note, disease within wild lion populations give rise to concerns with respect to translocations and the threat of transmission of pathogens.  Specifically, FIV is endemic within lion populations.  Hunter et al. suggest that FIV does not reduce infected lions’ lifespan or quality of life.  However, this is based on specific lion populations; namely those lions in the Serengeti and Ngorongoro.   As Troyer et al. (2011) note different strains of FIV result in different outcomes for the lion.  Those infected with subtype B, the predominant strain found in Serengeti and Ngorongoro lions, do not exhibit the high mortality rates evident in those lions infected with subtypes A and C.  They propose that “this could explain the lack of FIV-related pathology in the lions of the Serengeti, where FIV ple-B is the predominant circulating strain” (p. 344).  Hunter et al., make no reference to other strains of FIV, especially as regards FIV ple - E, circulating in Botswana, acknowledged to be an especially virulent and dangerous form (McEwan et al., 2008).

Hunter et al., refer to the two “catastrophic” CDV outbreaks in the Serengeti (1993-1994) and Ngorongoro Crater (2001) in which particular FIV clades were found to be more susceptible.  The effect is dismissed as “marginal”, yet the point remains that it was “statistically significant”.  These outbreaks were only 7 years apart and lead to “unprecedented mortality”. Troyer et al. (2011) suggest that although FIV was not considered a major factor in these deaths, there is evidence to suggest different strains within these populations may have played a supportive role as a result of immune suppression. Thus to make assumptions about the effects of FIV on lions in general, based on particular populations, and to judge two outbreaks which occur closely together in time and space as unusual, is dangerous.  There is perhaps some doubt in the authors mind about the soundness of such judgements as Hunter et al. retain a wise cautionary note that FIV may, at some point in the future, be shown to be detrimental to lion populations - although many research groups have already acknowledged this (e.g. O'Brien et al., 2012).  A solution is proposed to use FIV-negative wild lions, such as those in Etosha National Park.   So, the sample of lions being translocated to founder wild populations is actually smaller than first imagined: a point that seems to contradict the emphasis on maintaining genetic diversity within populations and attending to a complex array of factors. 

There are further concerns when the authors report the presence of bovine tuberculosis in lions.  The effect of bTB on lion populations is acknowledged by the authors as “poorly understood”, resulting in 30% of deaths in the inbred Hluhluwe-iMfolozoi population.  The primary reason given for not translocating infected lions from southern Africa is due to veterinary restrictions to protect livestock.  Where is consideration of the local community’s concerns about their livelihood as well as transmission of bTB across lion populations?   This is somewhat alarming.  How are the “biological, technical, financial and sociological factors” Hunter et al. accuse captive-origin reintroduction programmes for ignoring, being addressed here?  As the authors themselves correctly note, diseases in lion populations are not yet sufficiently understood and yet can cause significant populations decline (e.g. as seen in the Zambezi Valley in 1994/’95).  Therefore we cannot resolutely conclude that translocating infected wild lions will not have detrimental effects on lion populations.  If we are only to translocate the few unaffected ones, genetic diversity becomes an issue.

With respect to attending to genetic diversity within lions, organisations such as ALERT are accused of a lack of attention to genetic detail, creating a “mongrel captive population”, and are further charged with little regard for geographic lineage, further suggesting that lions are selectively bred for their tolerance of close contact with humans.  These are claims given no substantiation here. 

The authors highlight that marked inbreeding depression is known only in two isolated populations arising from extremely few founders: in the Ngorongoro Crater, Tanzania and Hluhluwe-iMfolozi, South Africa.  There is no indication of how many populations have been assessed for levels of inbreeding, whilst also failing to mention that the issue of inbreeding is significant in the wild-born lion translocation programmes touted as being such a significant success in lion conservation. (e.g. Trinkel et al., 2010).

The authors also offer comment on the behaviours of one of ALERT’s release prides, claiming they exhibit “maladaptive” and “aberrant” behaviours “unknown among cohesive social groups of wild founders”.  Firstly, the authors need to provide evidence to show that these are regular occurrences in programmes such as ALERT, and as such form the ‘norm’ for captive-born release prides.  Secondly why have known examples of such behaviour in wild lion prides been overlooked here?  Thirdly, behaviours such as filial infanticide are not unheard of in wild social species such as hyena (e.g. White, 2005).  

Hunter et al's paper has one main aim, to discredit the use of captive-origin lions, and in particular ALERT's programmes, as part of species restoration programs.  Unfortunately its attempts to do so preclude any detailed and rigorous evaluation of the programmes targeted.  The bottom-line is that neither wild-born nor captive-origin translocations can, on their own, resolve the problem in declining lion populations, yet both can play a part in an effective strategy to maintain, and where possible restore viable populations.  Point-scoring against other lion conservation programmes is not going to save the African lion.  Rigorous assessment and application of a range of effective conservation strategies might, to address those complex “biological, technical, financial and sociological factors”. 

Genuine attempts to redress the serious decline in wild lion populations are worthy of serious scientific engagement and assessment given the 80 - 90% population decline in lion populations overseen by the status quo of scientists and conservation organizations over recent decades.  The translocation of wild-origin lions has, the authors note, boosted lion numbers in certain areas, however such translocations have largely been motivated by tourism and not by conservation objectives.  Further, due to poor management at the correct social scale “these populations may be of limited value for the conservation of this species” (Slotow & Hunter, 2009).  The decline in lion numbers is a complex problem requiring a range of solutions.

The IUCN states: “The reality of the current situation is that it will not be possible to ensure the survival of an increasing number of threatened taxa without effectively using a diverse range of complementary conservation approaches and techniques including, for some taxa, increasing the role and practical use of ex situ techniques. If the decision to bring a taxon under ex situ management is left until extinction is imminent, it is frequently too late to effectively implement, thus risking permanent loss of the taxon.”  (IUCN, 2002).  The IUCN includes both a Reintroduction and Conservation Breeding Specialist Groups as part of it'sorganization..


African Parks (2012) African Parks Second Quarter Report 2012.  African Parks, Johannesburg, South Africa

Hunter LTB, White P, Henschel P, Frank L, Burton C, Loveridge A, Balme G, Breitenmoser C, Breitenmoser U (2012) Walking with lions: why there is no role for captive-origin lions Panthera leo in species restoration.  Oryx . Available on CJO 2012 doi:10.1017/S0030605312000695 

Hunter LTB, Pretorius K, Carlisle lC, Rickelton M, Walker C, Slotow R, Skinner JD (2007). Restoring lions Panthera leo to northern KwaZulu-Natal, South Africa: short-term biological and technical success but equivocal long-term conservation. Oryx, 41 , pp 196-204 doi:10.1017/S003060530700172X 

IUCN (2002) IUCN Technical Guidelines on the Management of Ex-Situ Populations for Conservation.  IUCN.

McEwan WA, McMonagle EL, Logan N, Serra RC, Kat P, Vandewoude S, Hosie MJ, Willett BJ (2008) Genetically Divergent Strains of Feline Immunodeficiency Virus from the Domestic Cat (Felis catus) and the African Lion (Panthera leo) Share Usage of CD134 and CXCR4 as Entry Receptors.  Journal of Virology 82 (21): pp 10953-8

O'Brien SJ, Troyer JL, Brown MA, Johnson WE, Antunes A, Roelke ME, Pecon-Slattery J (2012) Emerging viruses in the Felidae: shifting paradigms.  Viruses 4: pp 236 - 257

Slotow R, Hunter LTB (2009) Reintroduction decisions taken at the incorrect social scale devalue their conservation contribution: The African Lion in South Africa.   In: Reintroduction of Top-Order Predators (eds Hayward MW, Somers MJ), Wiley-Blackwell, Oxford, UK

Trinkel M, Funston P, Hofmeyr M, Hofmeyr D, Dell S, Packer C, Slotow R (2010) Inbreeding and density-dependent population growth in a small, isolated lion population.  Animal Conservation 13, pp 374 - 382

Troyer JL, Roelkea ME, Jespersen JM, Baggettb N, Buckley-Beason V, MacNulty D, Craft M, Packer C, Pecon-Slattery J, O’Brien SJ (2011) FIV diversity: FIVPle subtype composition may influence disease outcome in African lions. Veterinary Immunology and Immunopathology, 143, pp 338-346

White PA (2005) Maternal rank is not correlated with cub survival in the spotted hyena, Crocuta crocuta.  Behavioral Ecology, 16(3), 606-613



Further response to Born Free's "No Role for Lion Walking" (3rd September 2012)

ALERT is mentioned in Born Free’s “No Role for Lion Walking” post with a particular emphasis placed on a recent report published in July 2012 “Walking with Lions: Why there is no role for captive-origin lions (Panthera leo) in species restoration”. That paper, while dismissing the need for captive-origin lion restoration programmes and extolling the merits of wild lion translocation programmes as sound conservation, fails to produce conclusive evidence to assess either type of species restoration. 

ALERT acknowledges Born Free’s entitlement to their own opinions, but we do question Born Free’s particular negative emphasis of ALERT for three reasons. First, Born Free has not made the effort to visit ALERT’s programmes, and therefore cannot comment on the effectiveness of efforts to reintroduce captive-bred lions to the wild via staged programmes. Second, Born Free is greatly engaged in the practice of “saving” lions from captive situations; in some cases transporting such lions to the Shamwari in South Africa. These are good efforts in terms of animal welfare, but do not address lion conservation issues. Third, Born Free was established on the efforts of George Adamson who sought to reintroduce captive bred lions like Christian back to the wild. Born Free indeed features the viral YouTube video of George, John Rendall and Ace Bourke re-united with Christian in that lion’s attempted re-wilding programme.

ALERT would therefore seek to engage Born Free in constructive dialogue of means forward for best practices to reintroduce captive bred lions to the wild. ALERT invites Will Travers to the ongoing programmes in Zimbawe and Zambia to see for himself our efforts being made.    




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