Tarsius fuscus, whose distribution is limited to the southern part of South Sulawesi, Indonesia, is threatened by poaching and habitat loss, with the latter leading to the disappearance of its sleeping nest locations, despite the species’ wide range of habitat requirements. This study aimed to identify the distribution and characteristics of T. fuscus sleeping nests. Research took place in Bantimurung Bulusaraung National Park primary and secondary forest areas and Hasanuddin University Educational Forest. Sleeping nest locations were identified through vocalizations in the morning (4.30–6.00 am) and direct visual observations. Sleeping nest distribution maps were created using QGIS 3.16. Sleeping nests were found in karst rock shelters, Ficus trees, forest pandanus, and fallen tree debris, at elevations of 68–947 mdpl, 4–42° slopes, temperatures ranging 23.3–29.1°C, and distances to roads and settlements of 21.4–460.3 m and 325.9–1888.5 m, respectively. Tarsius fuscus tended to nest in primary forest rather than secondary forest, although this may also be caused by the larger proportion of primary forest. Protecting both primary and secondary forest is crucial, but particular focus should be given to the latter, owing to its susceptibility to human disturbance.

The population of the bear cuscus Ailurops ursinus (Temminck, 1824), an arboreal marsupial endemic to Sulawesi, Indonesia, and its satellite islands, is declining rapidly due to poaching and habitat loss, even in protected areas. However, despite concerns over its persistence, little is actually known of this secretive species. This research investigated the characteristics of the selected habitats and diet of the bear cuscus in four ecosystem types (lowland non-dipterocarp forest, lowland limestone forest, lowland monsoon deciduous forest, lowland monsoon evergreen forest). Habitat use data were collected through direct encounters and indirect observations (tracks, signs, secondary information), and analyzed using a chi-square goodness-of-fit test. Habitat characteristics and diet availability were determined using vegetation analysis. Diet data were obtained using direct observations, feed remains, and interviews. The lowland non-dipterocarp forest ecosystem was used significantly more by bear cuscus populations. Its habitats across the four ecosystem types had similar environmental conditions. Fifty-five plant species, eaten mostly as young leaves and leaf buds, encompassed the bear cuscus’ diet, with the Moraceae family being the most representative. Considering the ubiquity of Moraceae in the bear cuscus’ habitat, these results highlight the impact unchecked deforestation will continue to have on lowland Indonesia and its endemic species.