Ceratotherium simum ssp. cottoni

Status_ne_offStatus_dd_offStatus_lc_offStatus_nt_offStatus_vu_offStatus_en_offStatus_cr_onStatus_ew_offStatus_ex_off

Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA MAMMALIA PERISSODACTYLA RHINOCEROTIDAE

Scientific Name: Ceratotherium simum ssp. cottoni
Species Authority: (Lydekker, 1908)
Parent Species:
Common Name(s):
English Northern White Rhino, Northern White Rhinoceros
French Rhinocéros blanc du Nord
Spanish Rinoceronte Blanco del Norte
Synonym(s):
Rhinoceros simus subspecies cottoni Lydekker, 1908
Taxonomic Notes: In April 2010, Colin Groves and co-workers published a paper in which they argued, (based on morphological and genetic differences, estimated time since divergence from a common ancestor and using a phylogenetic species concept), that the Northern White Rhino (NWR) should now be considered as a separate species. Given there are a number of alternative ways to classify species there is unlikely to be universal agreement on the issue. Groves et al. (2010) paper has been criticised by some on a number of grounds and its recommendation has not been universally accepted. A detailed rebuttal of Groves et al. paper is also being prepared by a rhino geneticist. It is thus premature to come to a final conclusion on the issue at this time. It has also been argued that given conservation objectives the issue of whether or not Northern White Rhino should be treated as a species or subspecies is for practical purposes somewhat academic given: 1) the high degree of relatedness of the four remaining Northern White Rhinos at Ol Pejeta (calculated Founder Genome Equivalent of only 1.71);  2) the fact that any pure-bred offspring from remaining animals would  be inbred; 3) the need to maximise reproductive output from all these NWR animals (only one of which is young) to try to retain as many adaptive NWR genes as possible (by minimising loss of genetic diversity through genetic drift); and 4) constraints to reproductive output given that the two NWR males are old and there are only two NWR females and only one of these is a young animal. Conservation biologists Bob Lacy and Kathy Traylor-Holzer have advised that given the above situation and overall conservation objective, a stage has been reached where one doesn’t really have any choice of achieving medium to longer term conservation goals without trying inter-crossing NWR with Southern White Rhino so as to preserve some NWR genes within breeding populations that can hopefully later resume evolutionary adaptation to wild habitats. They have advised that even in the total absence of human-caused losses (e.g., to poaching), genetic and demographic modelling of such a small population of inter-related animals shows that the remaining four NWR are unlikely on their own to form a viable population in the longer term because of the negative effects of the severe inbreeding that would most likely occur, and the high probability of chance demographic events significantly reducing or eliminating the remnant population at some time before it has a chance to grow to safer numbers. Thus attempts at only pure breeding of NWR alone under these circumstances seem very likely to fail in the medium to longer term, and are at best might only be able to preserve inbred “museum specimens” that would not appropriately represent the original NWR. There can be no guarantee that this last-ditch attempt to conserve adaptive Northern White Rhino genes will succeed and inter-crossing may end up not being successful and in due course this would provide some support to Groves’ proposal that the NWR should be classed as a separate species.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered A2abcd; B2ab(i,ii,iii,v); C1+2a(i,ii)b; D; E ver 3.1
Year Published: 2011
Date Assessed: 2011-08-05
Assessor(s): Emslie, R.
Reviewer(s): Knight, M.H. & Adcock , K.
Justification:

The previous only confirmed wild population of the subspecies in the Garamba National Park and surrounding hunting areas in northeastern Democratic Republic of Congo is now considered to have probably gone extinct. There have been no reported live sightings of any of the last four rhinos since 2006 or their signs since 2007 despite an intensive systematic ground search looking for rhinos and their signs in 2008. Additional aerial searches and field range patrols have also not found any remaining rhino although one carcass has been found. While there are reports of a small number possibly surviving in a remote area of Southern Sudan these have yet to be substantiated. The only four potentially breeding rhino that were in Dvur Kralove Zoo in the Czech Republic have been moved to a private sanctuary in Kenya in the hope that the move to a more natural environment and natural diet and mixing with Southern White Rhino will encourage these animals to breed. However, due to a small effective founder number of only 1.71 (due to inter-relatedness of remaining animals) and based on Vortex modelling, in the absence of  finding any additional rhino in the wild, this subspecies is highly unlikely to be viable in the longer term. Unless some more Northern White Rhino are found in the wild, it appears that the best that can currently be hoped for is to conserve as many adaptive Northern White Rhino genes as possible for eventual reintroduction back to the wild, but this will require inter-crossing with Southern White Rhino.  

History:
2003 Critically Endangered (IUCN 2003)
2003 Critically Endangered
2002 Critically Endangered
1996 Critically Endangered
1994 Endangered (Groombridge 1994)
1990 Endangered (IUCN 1990)
1988 Endangered (IUCN Conservation Monitoring Centre 1988)
1986 Endangered (IUCN Conservation Monitoring Centre 1986)

Geographic Range [top]

Range Map:Click here to open the map viewer and explore range.

Population [top]

Population Trend: Decreasing

Habitat and Ecology [top]

Systems: Terrestrial

Bibliography [top]

Groves, C.P., Fernando, P. and Robovský, J. 2010. The Sixth Rhino: A Taxonomic Re-Assessment of the Critically Endangered Northern White Rhinoceros. PLoS ONE 5(4): e9703. doi:10.1371/journal.pone.0009703.

IUCN. 2011. IUCN Red List of Threatened Species (ver. 2011.2). Available at: http://www.iucnredlist.org. (Accessed: 10 November 2011).


Citation: Emslie, R. 2011. Ceratotherium simum ssp. cottoni. In: The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 22 September 2014.
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