The feeding behaviours of the Sulawesi babirusa (Babyrousa celebensis) were investigated in an enclosure imitating the early phase of a commercial coconut palm (Cocos nucifera) grove. Unexpected behaviours, such as the eating of coconut flowers and the picking of young coconut fruits, were observed. Additionally, we conducted experiments in which we fed several different parts of the coconut palm to the animals. We found the following: 1) coconut seedlings and leaflets were not eaten; 2) the babirusas preferred to eat staminate flowers rather than carpellate flowers; 3) the babirusas were able to crush the young coconut fruits with its teeth, but failed to open the mature coconuts; 4) the maxillary and mandibular incisors gripped the coconut, and the tip of the mandibular incisor was then used to penetrate the coconut surface to crack it open; 5) the palatable parts were the kernel and haustorium of the mature coconut.The coconut parts eaten by the babirusas in the experiment were concordant with the pieces of broken kernels and haustorium scattered over coconut groves in copra production. These pieces have no economic value for the farmer.There was insufficient evidence to support the view that babirusas moving through coconut groves constitute vermin for the coconut farmers and copra producers.

The impact of environmental stimuli on the expression of nesting behaviour of Sulawesi babirusa (Babyrousa celebensis) was explored over a period of 1339 days from 01 st August 2006 until 31 st March 2010 in a large animal enclosure on Bali, Indonesia. We found that nest building behaviour and the re-use of sleeping nests occurred more frequently in the dry season than the wet season and was clearly influenced by both a drop in the ambient temperature and an increase in wind speed. Additionally, net effective temperature (NET) computed from a combination of ambient temperature, relative humidity, and wind speed indicated a close relation to the nesting behaviour frequency; a decreasing trend of the expression rate of nesting behaviour with increasing NET in the early evening. Moreover, the trend of the expression rate by 12-hr NET fluctuation from 05:00 hr to 17:00 hr was also found out in all seasons. Meanwhile, 24-hr rainfall had a negative impact on the expression rate. These findings suggested that NET was a useful meteorological index to discuss the motivation to exhibit the nesting behaviour of babirusa, and also babirusa probably found thermal comfort in the sleeping nest.