Telah dilakukan penelitian pada kukang sumatra (Nycticebus coucang Boddaert, 1785) di Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI). Tujuan penelitian untuk mengetahui perilaku reproduksi N. coucang betina terhadap jantan di YIARI dengan pengamatan sepanjang siklus estrusnya. Penelitian dilakukan terhadap dua individu kukang sumatra betina dewasa (Ulul dan Lea) dengan perbedaan riwayat melahirkan. Metode penelitian yaitu All Occurrence Sampling dan Ad Libitum Sampling. Penelitian dilakukan selama bulan Oktober hingga November dari pukul 19.00--03.00 WIB. Perilaku reproduksi yang diamati meliputi tiga kategori yaitu atraktivitas, proseptivitas, dan reseptivitas. Hasil penelitian menunjukkan N.coucang betina melakukan hampir seluruh perilaku yang diamati, yaitu vokalisasi (whistle call) (27%), solicit (6%), urine marking (58%), recipient genital sniffing/licking (3%), inverted embrace (1%), menolak kopulasi (5%), sedangkan perilaku menerima kopulasi (0%) tidak teramati. Selain itu terdapat perbedaan perilaku reproduksi antara Ulul dan Lea. Perilaku reproduksi Ulul lebih rendah dibandingkan Lea. Panjang periode estrus Ulul tidak diketahui, sedangkan Lea berkisar antara 10--11 hari dengan lama estrus satu hari.

---

Research on sunda slow loris (Nycticebus coucang Boddaert, 1785) has been carried out at the Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI). The aim of the study was to determine the reproductive behavior of N. coucang females against males at YIARI with observations throughout the estrus cycle. The study was conducted on two adult Sumatran slow loris individuals (Ulul and Lea) with differences in delivery history. The research method was All Occurrence Sampling and Ad Libitum Sampling. The study was conducted from October to November from 7:00 to 3:00 WIB. Reproductive behavior observed include three categories, namely attractivity, proceptivity, and receptivity.

The results showed that N. coucang females carried out almost all observed behaviors, namely whistle calls (27%), solicits (6%), urine marking (58%), recipient genital sniffing/licking (3%), inverted embrace (1%), refused copulation (5%), while the behavior of receiving copulation (0%) was not observed. In addition there are differences in reproductive behavior between Ulul and Lea. Ulul reproductive behavior is lower than Lea. The length of the Ulul estrus period is unknown, while Lea ranges from 10--11 days with one day long estrus.