Print size in Rhinoceros sondaicus . Schenkel & Schenkel-Hulliger assigned age/sex categories to the Ujung Kulon rhinos using Indian Rhino standards. This was of course a `faut de mieux' strategy, and I have never been entirely convinced about it. The biggest Javan rhinos would be about equivalent in size to Indian females (about 1500 kg): the fully mature Indian male weighs >2000 kg, a figure equalled among rhinos only by Ceratotherium simum simum. Hoogerwerf always maintained that age measurements would a little lower; footprints of 24-25 cm would belong, according to him, to animals of 2-3 years old (whereas the Indian female Nanda in Basel Zoo, used to set the standards by the Schenkels, already had a forefoot diameter of 26 cm at 2 years, 8 months). The Cat Loc census would, if this were correct, record two full adults, and probably 1-2 subadults, plus 4-5 young. The age ration is still odd, but not quite as odd as before. Possible explanations: (1) Haryono et al. report that 10 were poached since 1981. I'm not sure whether one could suppose that adults predominated in this total; they do not give the dates when the poaching incidents took place but, if some had been only shortly before their census in 1983, this might account for the shortage of full-sized adults. (2) The well- documented phenomenon of an expanding population breeding at younger ages than one at carrying capacity? The Schenkels assumed that, like the Indian rhino, the Javan rhino is sexually dimorphic so that the largest footprints would be those of males. This is definitely not correct. Hoogerwerf thought that females are the larger sex; Gu?rin agreed with him. I am not so certain about that, but my craniometric data show clearly that there is no male hypermorphosis such as occurs in the Indian rhino; to all intents and purposes the two sexes are the same size. Nothing is known about whether the female of R.s. annamiticus is/was well-horned or not; but on the analogy of the other two subspecies, it might be supposed that decent horns in females are vanishingly rare. I would suppose that females got shot for the same reason as African poachers shoot dehorned rhinos: they want to eliminate an unproductive set of tracks.
effect of UV light. I have seen the facilities for the Sumatran rhinos in Jakarta, San Diego and Melaka. Those in Melaka are the best, but I would like to make a comment which applies even to this one: too much sunlight. Recently Julian O'Dea, a Visiting Fellow in the Division of Archaeology and Natural History, A.N.U., made UV-B measurements in North Queensland rainforests, and compared them with those made in the open nearby. The results are dramatic, and unanticipated: microwatts per cm? : Time Outside conditions outside inside 11-1 strong sunlight 189-245 0-4 11-2 fairly overcast 68-156 0-5 (6 in a small clearing) 4pm overcast, rain 30 0 9am clear sky 70 0-5 - winter in Canberra 80 0-4 This means that Sumatran rhinos - in fact, any terrestrial rainforest animal - will get far too much UV radiation if kept even partly in the open. The prevalence of cataracts in the captive stock supports this conclusion. I speculate that, in addition to this, they will be too hot and, especially, too dry outside the humid rainforest microclimate. I stress that all three zoos have obviously been concerned to keep their rhinos in the best possible conditions. These observations are offered in that spirit.
