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| The Critically Endangered Sumatran rhinoceros
Dicerorhinus sumatrensis formerly ranged across Southeast
Asia. Hunting and habitat loss have made it one of
the rarest large mammals and the species faces extinction
despite decades of conservation efforts. The number of individuals
remaining is unknown as a consequence of inadequate
methods and lack of funds for the intensive field
work required to estimate the population size of this rare
and solitary species. However, all information indicates
that numbers are low and declining. A few individuals persist
in Borneo, and three tiny populations remain on the
Indonesian island of Sumatra and show evidence of breeding.
Rhino Protection Units are deployed at all known
breeding sites but poaching and a presumed low breeding
rate remain major threats. Protected areas have been created
for the rhinoceros and other in situ conservation efforts
have increased but the species has continued to go locally
extinct across its range. Conventional captive breeding has
also proven difficult; from a total of ?? Sumatran rhinoceros
taken from the wild since ???? there were no captive births
until ????. Since then only two pairs have been actively bred
in captivity, resulting in four births, three by the same pair at
the Cincinnati Zoo and one at the Sumatran Rhino
Sanctuary in Sumatra, with the sex ratio skewed towards
males. To avoid extinction it will be necessary to implement
intensive management zones, manage the metapopulation
as a single unit, and develop advanced reproductive techniques
as a matter of urgency. Intensive census efforts are ongoing
in Bukit Barisan Selatan but elsewhere similar efforts
remain at the planning stage. | |
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