Hooo-Hooo Volume 10, nr 4 - Page 15

Horn growth The average weight of the horn of a white rhinoceros bull is 5 kg. It is likely, therefore that on the first harvest an adult male will yield 3.16 kg of horn, and adult female 2.02 kg of horn, a sub-adult male 2.16 kg and a sub-adult female 1.02 kg of horn (Refer to Chapter 27). The estimated harvest is 65% of the total horn available of the animal. The regrowth of the horn if cut correctly as described above is an average of 2 kg for a cow that can be harvested every two years. The growth will depend on how active animals will use their horns to mark their territories. One of the suggested reasons for the failure of the Hwange National Park dehorning was that the rhinoceroses carried at least 18 months of re-growth when they were poached (Lindsey & Taylor, 2011). However ranchers dehorn their animals twice per year to limit the risk of poaching. Population size that must be dehorned To prevent poaching the aim must be to dehorn hundred percent of the population. The dehorning of animals as a commercial exercise it is recommended not to dehorn a rhinoceros younger than 4 years. Depending on the age and sex ratios 50% of a population must be dehorned at the same time. A cut can be made in the toe nail that will indicate to poachers that the rhinoceros is dehorned. Tourism Purists feel that tourists want to see a rhinoceros with a horn. However, dehorning could actually benefit tourism operations by demonstrating that ranch owners are actively trying to do something to prevent poaching. This factor will be determined how active tourist operators market the dehorning of animals under their clients. The question must be asked – is a tourist happy with this image? Storage risks Security is a major risk. Private landowners in South Africa store their horns in a variety of locations, typically in vaults located off the property such as banks. There is a risk that government officials can leak information of dehorning operations to syndicates. A case is known where the permit was issued and followed by an armed robbery the next day. However, faked robbery can also happen where the horns are removed legally and afterwards robbed. The cost to store 10 kg of horn in a private bank safe is ZAR 120 per annum. There is risk that insects may cause damage to the horns during the storage period. In the past naphthalene moth balls were used, but the poison can cause harm to humans. Currently diatomite is recommended as described in Chapter 23. Horns can dry out if stored for long periods. The Table 17.1 below indicates that 0.6 % per annum is lost over a period of 17 years. Table 17.1: Weight loss in rhinoceros horn RHINOS No WEIGHT (g) WEIGHT (g) WEIGHT LOSS (g) WEIGHT LOSS (%) 24/04/ 1995 04/05/ 2012 17 years 17 years 3 1325 1218 107 8,00 4 2149 1870 279 12,98 6 1644 1508 136 8,27 TOTAL 5118 4596 AVERAGE/ YEAR 522 10,19 30.7 gram 0,60 % Ecological Conservationists feel that a rhinoceros bull needs his horn to protect its territory and a cow to protect her calf against predators. There are no scientific studies based on a control where a certain group of animals are not dehorned. However, a case is known where an adult bull was dehorned and soon after dehorning killed an adult cow. It is not recommended to dehorn animals in wilderness areas where lions occur. References Lindsey, P.A. & Taylor, A. (2011). A study on the dehorning of African rhinoceroses as a tool to reduce the risk of poaching. Report Department of Environmental Affairs. 2016 SEPTEMBER 15