Telah dilakukan penelitian mengenai aktivitas pair bonding pada siamang Symphalangus syndactylus (Raffles, 1821) di Primate Center, Taman Safari Indonesia Bogor, Jawa Barat. Tingkat kekuatan pair bonding dapat dipengaruhi oleh perilaku afiliatif, tingkat sinkronisasi, dan lama waktu berpasangan. Penelitian bertujuan untuk mengidentifikasi dan menganalisis aktivitas pair bonding kedua pasangan siamang. Subjek penelitian adalah dua pasangan siamang. Pasangan siamang 1 pernah menghasilkan keturunan dan mengalami pemisahan, sedangkan pasangan siamang 2 mengalami pemasangan dengan individu baru. Penelitian dilakukan selama 6 pekan terhitung dari Maret hingga April 2023 selama 5 hari dalam satu pekan. Penelitian dilakukan bergantian setiap pekan dengan 15 kali pengulangan untuk masing-masing pasangan. Metode penelitian yang digunakan adalah scan animal sampling dan ad libitum dengan interval waktu 10 menit tanpa jeda. Berdasarkan hasil penelitian, aktivitas pair bonding yang teridentifikasi adalah behavioral synchrony, close proximity, body contact, allogrooming, dan duet vocalization. Berdasarkan uji Mann-Whitney pada α = 0,05 menunjukkan bahwa terdapat perbedaan secara signifikan pada perilaku behavioral synchrony dan close proximity antara kedua pasangan siamang. Seluruh perilaku yang mengindikasikan pair bonding dapat teramati pada kedua pasangan siamang, perbedaannya adalah tidak teramati peristiwa kopulasi dan masih teramati perilaku agonistic gesture pada P2. Penerapan aspek kesejahteraan satwa melalui prinsip Five Freedoms of Animal Welfare pada siamang telah terpenuhi dengan baik melalui upaya pemeliharaan yang telah dilakukan.

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Research has been conducted on pair bonding activities on siamang Symphalangus syndactylus (Raffles, 1821) at Primate Center, Taman Safari Indonesia Bogor, West Java. The level of pair bonding strength can be influenced by affiliative behavior, the degree of synchronization, and the length of time in pairs. This study aims to identify and analyze the pair bonding activities of both siamang pairs. The subjects studied were two pairs of siamang. The first pair has produced offspring and experienced separation, while the second pair is pairing with new partner. This study was conducted for 6 weeks from March to April 2023 for 5 days a week. This study was conducted alternately every week with 15 repetitions for each pair. The research method used were scan animal sampling and ad libitum with 10 minutes intervals without pause. Based on the results, pair bonding activities identified were behavioral synchrony, close proximity, body contact, allogrooming, and duet vocalization. Based on the Mann-Whitney test at α = 0.05 showed a significant difference in behavioral synchrony behavior and close proximity between both siamang pairs. All behaviors that indicate pair bonding can be observed in both siamang pairs, the difference is no copulation observed and agonistic gesture behavior still observed at P2. The implementation of animal welfare aspects through the principle of Five Freedoms of Animal Welfare in siamang has been well fulfilled through maintenance efforts that have been carried out.