CHRISMOND SEM PASAN¹

Deer Cave in Mulu National Park houses a colony of several million wrinkle-lipped bats (Chearephon plicata). The sight and sound of these bats when they leave the cave in the evening is one of the main attractions of the Park for visitors. However, the bats do not come out every evening, and it is not possible to predict when they will not emerge.

Mulu National Park is about 110 kilometres south-east of Miri in the northern part of Sarawak. Deer cave is one of the main visitor attractions among the four show caves of Mulu and is the world’s largest cave passage as it is 1.6 kilometres long, 100 metres wide and 120 metres high (Meredith et al,1992). Deer cave is situated 3.1 kilometres from Mulu park headquarters along boardwalk and concrete trails. The bat observatory shelter is about 100 metres from the cave entrance, and is provided with lighting and washroom facilities.

Hall (1992) listed twelve species of bats recorded at Deer cave, with wrinkled-lipped bats (Chearephon plicata) being the most numerous. Hall (1992) developed a method based on photographs to estimate the number of bats flying out; on seven evenings between 1988 and 1993, numbers varied from none to 1.8 million, and many bats remained in the cave even after the largest number had left.

The large bat flights are spectacular: they fly in huge wheeling flocks or long sinuous clouds, accompanied by a great whooshing roar of thousands of pairs of wings.

This survey was carried out for six days from 21 to 26 June 2001. The number of visitors who returned from the cave without waiting for the bats to come out was noted, and questionnaires were distributed to those who waited at the bat observatory.

Three hundred visitors (205 Asians and 95 Europeans) went to Deer Cave during the survey period, and 98% waited for the bats to come out. Of these, 198 returned the questionnaire forms.

Some visitors (10%) had seen the bats at Deer Cave before, and 14% had seen similar bat flights in other places.

Most respondents (91%) said they were happy or very happy that they had stayed to watch the bats come out; details are shown in Table 1. The bats came out each evening during the six day survey and visitors’ satisfaction would probably be less if they had not come out.

Table 1 : Ranking of visitors satisfaction

Occasionally visitors leave Deer Cave as soon as the first bats emerge, but that did not happen during the study: all visitors waited for a lot of bats to come out and for numbers to tail off before leaving.

People were very interested in the bats and asked me many questions. There is a need for more interpretation at the bat observatory, perhaps in the form of displays.

The bat flights are obviously an important part of the visitors experience at Deer Cave, as almost all stayed to see them. On evenings when the bats come out, visitor satisfaction is high. Similar surveys of visitors satisfaction should be done on evenings when bats do not come out. No data are available on the percentage of evenings when bats emerged from the caves and these need to be collected.

We need more information on bats, as there are many unanswered questions about bats in Mulu. Many mysteries still surround these bats, perhaps the most important question is: where do they go for feeding and how far do they fly out? (Meredith and Wooldrige, 1992).

Hall, L. S. (1996). Observation on bats at Gua Payau (Deer Cave). Sarawak Museum Journal. No.71 (New Series) 1996: 118-122.

Meredith M. and Wooldridge J., Lyon B. (1992). Giant Caves of Borneo. Tropical Press Sdn,. Bhd., Kuala Lumpur. Pp.64-66.