JSPS 先端拠点形成事業による派遣研究者研究報告書

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1 平成 25 年 8 月 27 日 JSPS 先端拠点形成事業による派遣研究者研究報告書 所属部局 職 Wildlife Research Center, Kyoto Univ. 氏名 Wan-Ting Hong 1. 派遣国名 Malaysia 2. 研究課題名 Preliminary observation of Bornean slow loris 3. 派遣期間 ( 本邦出発から帰国まで ) 平成 25 年 6 月 25 日 ~ 平成 25 年 7 月 28 日 (34 日間 ) 4. 主な受入機関及び受入研究者 Dr. Henry Bernard, Universiti Malaysia Sabah 5. 所期の目的の遂行状況及び成果 ( 研究内容 調査等実施の状況とその成果 ) See Report on preliminary research of slow loris in Kabili-Sepilok Forest Reserve 6. その他 ( 特記事項など ) 特になし

2 Report on preliminary research of slow loris in Kabili-Sepilok Forest Reserve Purpose During this preliminary research, I tried to: (1) carry out night surveys and learn how to do fieldwork during the night, including acquiring skills of finding slow lorises, getting familiar with night forest and testing of equipment I ve got, (2) observe as much as possible and gain as much information as possible about the basic ecology and behavior of slow loris, and try to come up with research topic from questions that occurred to me during my survey and observation, and (3) prepare for future work, find out whether the number of slow lorises here is enough for my study, how high they are and if they are easy to catch, who can catch it and which vet should I contact. In this trip to Malaysia, I also tried to find myself a local collaborator in UMS, visit officers in Forestry Department and SaBC and submit necessary documents for application of research permit. Method Night surveys were conducted along established human and animal trails in Orangutan Rehabilitation Center and Rainforest Discovery Center (RDC), both of which are located within Kabili-Sepilok Forest Reserve. Surveys were conducted between 19:00 and 23:00, during which I used a flash light (GENTOS DC205F, 200 lumens) to search for the characteristic orange eye-shine of slow lorises. Whenever an eye-shine was detected, I put on binocular and tried to take picture to confirm the identity of the species. The following information was recorded for each sighting: time of sighting, location, number of individuals, height of individuals with respect to the ground, activity when first detected, species of plant the animal is located in, part of the plant the animal is sitting on, and, if possible, their sexes and estimated age-classes. Also I recorded the weather and brightness of the night, to see if they are more active during wet/dark nights as the previous studies suggested. Beside direct observation, I also interviewed experienced local rangers who have often spotted slow loris. Result and Discussion 1. Result of the night survey

3 Figure 1. First slow lorises encountered in this research (a female adult) I went on night surveys for 17 days by myself or with my assistant, with a total time of 43.5 hours and walking speed between m per hour (to know which walking speed is best for spotting slow lorises, I changed walking speed time to time). When we didn t go on a night survey or when we finished earlier before 11 pm, it was either because of heavy rain, equipment (mostly flashlight) broken down, or my assistant s ask for a rest. Beside night survey, I also went on day walks to get familiar with the forest. In total I walked for 8 hours, with walking speed about 1748 m per hour. Table 1. Basic information of slow lorises encountered during this research # Date Age/sex Spotted - Lost Duration Part Height Tree species 1 7/3 Adult female 19:16-19:34 18 terminal 4 Kayu ara (pregnant) 2 7/16 Juvenile 19:46-19:58 12 middle 6 Tapai tapai 3 7/17 Male infant 19:40-20:55 75 terminal 10 Katapang 4 7/18 Female infant 20:10-20:56 46 trunk, 9 Kayu pelindung middle, terminal 5 7/22 Adult 21:14-21:14 1 trunk 20 Kayu ara 6 7/23 Male juvenile 19:15-20:33 42 middle 10 Tapai tapai 7 7/23 Female 21:12-21:45 33 middle, 15 Kayu pelindung juvenile or terminal adult During 17 days, I spotted 7 slow lorises, among them 3 females, 2 males, and 2 with unidentified

4 sex. Of all the 7 slow lorises spotted, 2 of them were adults (one pregnant), 3 of them juveniles and 2 of them infants. Mean observation time is minutes per animal. Often they were found meters high on the tree. Tree species they preferred include Kayu ara (twice), Tapai tapai (twice), Kayu pelindung (twice), and Katapang (once). According to rangers who had seen slow lorises before, slow lorises can also be found on Mata kuching and Kayu laran. Some local people said they found slow loris sleeping on Cacao tree during the day. They also said farmers won t dispel slow loris from the tree because slow lorises eat the insects that harm Cacao trees. 4 of the slow lorises were found in extremely bright night; bright moon does not discourage slow lorises from going out. 2. Ecology and behavior of slow lorises (1) Diet: A. What they eat Table 2. Food of slow lorises in Kabili-Sepilok Forest Reserve Plant food of slow loris Animal food of slow loris Tarap Grasshopper Rambutam Caterpillar Langsat Stick insect Moth Larva in the leaves / bark Despite the fact that not a single feeding event was observed during this preliminary research, through interviews with experienced local rangers, we know that animal food of the slow lorises population here in Sepilok have had includes grasshoppers, caterpillars, stick insects, moths, and insect larvae in the leaves or bark. Slow lorises also consume fruits, among them their favorite being Tarap, Rambutam, and Langsat. Fruiting season in Sepilok is from August to December, with flowers coming out first in September. Previous studies have suggested that slow lorises in west Malaysia (greater slow loris) consumed mainly nectar, gum and sap, with fruit and arthropods comprising only a small portion of the diet (Wiens 2002, Wiens and Zitzmann 2003). On the other hand, pygmy slow lorises were suggested to be the most insectivorous of all slow lorises. Consumption of insects, including ants and moths, is relatively common; and processing of these prey items mirrors that of slender lorises (Streicher, 2004). Since no feces analysis has been carried out on Bornean slow lorises, details of their diet remains unknown. It is very possible that Bornean slow loris follows the pattern of pygmy slow loris instead of greater slow loris. More details regarding their diet, spacing and mating system of this population might be available during this period.

5 B. How they eat Insects can be found easily in young leaves at the end of a branch. Researchers have suggested that, this 3-dimensional feeding environment has resulted in slow lorises having the greatest degree of orbital convergence of all primates. When I spotted slow lorises, I often found them on their way to the end of the branch. However, because slow lorises are shy and the population here in Sepilok is obviously not habituated yet, they either ran away, stay frozen on the same spot or moving up and down and not continuing their business when they were disturbed by the presence of observers. If cameras can be set on the end of the branch, we can get to know many interesting details regarding their feeding behavior, such as whether they use one hand or both hands to catch, which hand do they prefer to use, etc. (2) Habitat preference All the sightings of slow loris occurred in Orangutan Center. I have never spotted slow loris in RDC, although I think RDC should be a better place for slow loris because of high level of disturbance from tourists in Orangutan Center (around people every night). One of the reasons that it is easier to spot slow loris in Orangutan Center is probably because you can focus on fewer trees and search the same tree from different angle again and again. In RDC, we never search the same tree again. The other reason, which is probably more important, is the possibility that slow loris prefers forest edge and secondary forest over primary forest. If this is true for this population of slow loris, it has not yet been reported by any previous study. They can be attracted by fruits people grow. Experienced rangers suggested me to include other sites with medium level of human disturbance, such as Jungle Resort. (3) Stress from tourists

6 Figure 2. Female slow lorises escaped right to the top of the tree when discovered by observers Figure 3. Juvenile slow loris froze in the same place when discovered by observers

7 Figure 4. Male juvenile froze when discovered by observers Figure 5. Male juvenile froze when discovered by observers In spite of an endless flow of tourists every night, slow lorises here were still not habituated. When they were disturbed, they stopped their own business and often became frozen or moved back to the trunk and moved up and down as if they couldn t decide to go home or to continue. This situation happened a lot on younger individuals or males. They often resumed their movement

8 after most of the observers (tourists) were gone. On the other hand, pregnant mother, for example, fled right to the top of the tree and disappear in the dense canopy so that we couldn t follow it. On one night, I saw another female slow loris that ran so fast on the branch that she reached the speed of 1 mete per second. Regarding other behavior observed, I often observed them scratching themselves in the presence of humans. It is possible that this population of slow lorises is under great psychological pressure. I think it would be interesting if I can compare the stress level of slow lorises here with slow lorises from other habitat (maybe primary forest). Difficulties The technical problems I encountered so far were as following: 1. The problem of finding animals: we can only find animals by their eye shine. What if they don't turn their head toward us? It is very difficult to distinguish their body from dead leaves on the tree. Often, I tried to search a tree from different angle. Sometimes I tried to make sounds, so that they might turn their head toward me. 2. The problem of identifying and observing the animals: my headlamp was broken even before I used it. Thus, I had to rely solely on my flashlight (200 lumens), which I found was still too weak. I usually couldn't take pictures with my flashlight. Moreover, the animal can appear very far or very high, and I couldn't identify the species of the animal and what they are doing even with my binocular. Several times, I lost the animal when I tried to put on my binocular or tried to set the camera. Also, the laser range finder didn t work in the night. I have to think all over again what equipment is necessary for observing animals clearly, and how to record their behavior using camera during the night. I think using video to record behavior is a good option. For that, I will need camera that can zoom in very much, a tripod and very strong lights. I will also learn more about night vision and I will figure out what can replace a laser range finder. 3. The problem of following animals: sometimes when the animal noticed the observer's presence, it retreated deeper into the forest. To follow the animal, we had to cut trees and watch our foot when going deeper into the forest. It is at this point that we are likely to lose their sight. Preparation for future work: collecting DNA To collect DNA samples for information about their population structure, genetic diversity, diet and mating system, and probably for the comparison of the level of stress of slow lorises of different habitats, I plan to capture slow loris and take hair or feces sample from them. Some of the local rangers have experience catching slow loris. They caught by hand using a net, or by wire mesh traps baited with bananas. One of the ranger said he can catch slow loris for me. Also there

9 are several vets in Orangutan Center who can help with handling the animals. I will contact Dr. Nigel when I get the permission to catch the animal. I plan to bring DNA samples back to Japan for analysis. For this, I will have to apply for export license around October. Because it is better to have some former experience in handling the sample, I plan to collect feces and hair samples of slow loris (or other prosimians) around zoos in Japan. About local collaborator and research permit (access license) I have already met Dr. Henry Bernard in UMS and talked with him about my research plan. He agreed to help and sent me a letter of support soon after that. At the time he was just looking for students to do research on slow loris. He seems to include slow loris in his SAFE project. I think it will be good if I have time to join some part of the SAFE project. I can follow a group of primatologists and learn field method with them. Regarding research permit, I met officers in SaBC and Forestry Department. I got permission to go into the forest immediately. Then I submitted all documents necessary for application of research permit to SaBC before their meeting on the 2 nd week of July. I should be able to get the permit soon. References Streicher, U. (2004) Aspects of the ecology and conservation of the pygmy loris in Vietnam [inaugural diss.]. Ludwig-Maximilians University, Munich Wiens, F. (2002) Behavior and ecology of wild slow lorises (Nycticebus coucang): social organization, infant care system and diet [PhD diss.] Bayreuth University, Bayreuth Wiens, F., and Zitsmann, A. (2003) Social dependence of infant slow loris to learn diet. Int. J. Primatol. 24: