Photo 6. Boat patrol of RPUs in Way Kambas National Park . Photo by Cyril Ruoso SRS
Photo 7. The RPU of Way Kambas patroled across a stream areas . Photo by Cyril Ruoso SRS
Map 3: U
2.1 Numbers and Trends
From the mid 1960s and the early 1980s, Javan rhino numbers slowly grew from an extremely small number of about 25 animals to about 60 animals. It appears that since the early 1990s a
slightly negative trend has set in, with current rhino numbers estimated to be around 50 Figure 4. If the current trend continues a growth rate of -0.7 year, the Javan rhino population in
Indonesia will halve before the end of the century.
RHINO CENTURY PROGRAM
Figure 4
80
An analysis of 220 camera trap photos taken by WWF from 2000–2004 reveals that in most years, about the same number of animals with and without sizeable horn were photographed.
However, in 2000 and 2003, a substantially larger number of animals were photographed carry sizeable horns. It has been suggested Griffith, 1993 that only males carry sizeable horns,
although Schenkel and Schenkel 1969 did not find a correlation between sex and horn size. The sex composition of the Ujung Kulon rhino population remains unclear; there is no verification
of the suggestion that there is an over-abundance of males.
Figure 5
Using the same photographs, an attempt was made to identify age classes of the animals Figure 6. In the pictures collected between 2000 and 2004, 65 were of adult animals, 20 were of
sub-adult animals and for 15 of the animals, age class could not be determined. While these data are inconclusive the same animal might appear on several pictures while other animals
might not have been photographed, it appears that there are no immediately apparent imbalances in the age structure of the population.
Pictures of a calf were collected only in 2002. Thereafter, small footprints have occasionally been encountered by the RPUs and the WWF camera trap team.
This lack of evidence of reproduction is cause for concern. It may be that reproductive behavior is diminishing due to
limitations in available habitat.
RHINO CENTURY PROGRAM
