Mentilin jarang sekali bersuara, meskipun kita berada didekatnya. Hewan ini lebih banyak diam terutama di siang hari. Namun, di malam hari Mentilin terkadang bersuara. Wajar karena malam hari adalah waktu aktivitasnya (hewan nokturnal). Tapi Mentilin juga bisa berteriak di siang hari ketika merasa panik, misal saat ditangkap oleh animal keeper-nya.
Jadi sebenarnya hewan endemik Bangka ini bisa ngobrol nggak sih dengan sesamanya? Yuk kita bahas.
Studi yang mendeskripsikan suara Mentilin (Chepalopacus bancanus) pernah dilakukan oleh Yustian et al. (2021). Ia merekam suara Mentilin dari jam 5 sore hingga jam 7 pagi selama 3 malam berturut-turut. Tercatat terdapat 7 jenis suara yang polanya berbeda.
Ada suara squeak yang hanya dikeluarkan oleh bayi Mentilin (Gambar 1), suara siulan dan ciutan yang muncul dari bayi dan Mentilin dewasa, dan 4 jenis suara lain yang hanya dikeluarkan oleh Mentilin dewasa. Diduga suara yang dapat dibunyikan oleh bayi dan Mentilin dewasa adalah cara bayi dengan induknya berkomunikasi.
Ada pula teriakan agonistik yang bisa mencapai tingkatan ultrasonik, yaitu diatas 20.000 Hz yang terjadi ketika terjadi kontak antara dua individu jantan (Gambar 2). Maklum, Mentilin Bangka adalah hewan yang suka menyendiri (soliter) dan teritorial. Berbeda dengan kerabat dekatnya, tarsius dari Sulawesi Utara yang cenderung hidup berkelompok meskipun kelompok kecil (2-8 individu) (Arrijani & Rizki 2020).
Sedangkan teriakan yang lebih keras lagi terekam saat Mentilin merasa panik saat sedang dipegang atau ditangkap, suara ini disebut Yustian (2021) sebagai Distress call (teriak peringatan) dan Hysteresis (efek stres yang lama). Bisa dilihat dari garis spektogramnya yang tebal dan tinggi (Gambar 3).
Dari ketujuh jenis suara yang dideskripsikan ini, kita bisa tahu bahwa Mentilin memiliki vokalisasi yang masih bisa didengar manusia. Yustian (2021) hanya menangkap suara ultrasonik ini berbarengan dengan suara teriakan yang mulanya terdengar oleh kita.
Namun pada penelitian Gursky (2013) terhadap kerabat mentilin di Filipina, Tarsius syrichta atau sudah berganti nama Carlito syrchta (Ini pernah kita bahas di artikel sebelumnya!), terekam sebanyak 10.309 suara ultrasonik. Rekaman suara ini dikumpulkan selama 3 bulan, kemudian dikelompokkan oleh Gursky menjadi 3 jenis suara yaitu chirp (cicit), twitter (kicau) dan whistle (siul). Gursky sendiri menyebutkan bahwa studi ini adalah penelitian awal, sehingga fungsi dari vokalisasi tarsius ini masih merupakan dugaan. Diduga bahwa vokalisasi ultrasonik ini digunakan untuk berkamuflase dari predator. Supaya komunikasi antar sesamanya tetap sampai namun tidak menjadikannya mudah ditemukan predator. Gursky mengatakan bahwa dia dan asisten lapangannya melihat Tarsius itu mangap tapi nggak ada suaranya!.
Selain itu di dalam diskusinya, Gursky menjabarkan kemungkinan suara-suara ‘yang tak bisa kita dengar’ ini bisa membedakan antara satu spesies tarsius dengan spesies tarsius lainnya. Ini fakta yang sangat menarik, kenapa?.
Ilmu ekologi dan konservasi sudah begitu majunya sampai dimana untuk analisis kondisi lingkungan, kita cukup merekam suara disana. Ini disebut bioacoustic monitoring yang bertujuan untuk mendata keberadaan, distribusi, dan tingkah laku hewan di alam. Metode ini menjadi pendekatan yang efektif dan inovatif dalam monitoring satwa, khususnya individu yang telah dilepasliarkan pasca proses penyelamatan. Selain mempercepat proses identifikasi dan pemantauan tanpa harus intens menjelajah, teknik ini bersifat non-invasif, sehingga tidak menyebabkan stres atau gangguan pada satwa. Bahkan tanpa interaksi langsung, peneliti dapat memperoleh data yang berguna untuk memahami dinamika populasi satwa di habitat alaminya.
Namun, untuk sampai kesana, disinilah kita perlukan penelitian untuk mengetahui sistem vokalisasi Mentilin. Dari sana kita bisa menentukan suara-suara yang dapat dijadikan indikator, apakah Mentilin stres atau berhasil berbaur dengan lingkungannya. Jadi, ada yang tertarik untuk penelitian disini?
Manajemen pemeliharaan Mentilin di Pusat Penyelamatan Satwa Alobi (PPS Alobi) telah dievaluasi positif berdasarkan beberapa aspek, di dalam studi oleh Dalimunthe et al. (2024) dari Universitas Muhammadiyah Bangka Belitung. Aspek yang dinilai antara lain yaitu bentuk kandang yang mengambil model kandang outdoor dan dibuat semirip mungkin dengan habitatnya dengan menyediakan batang dan dahan pohon. Pemberian pakan juga disesuaikan, dimana Mentilin Bangka disini diberi pakan jangkrik, belalang, dan sesekali ulat bulu. Pemberian pakan dan penggantian air minum dilakukan oleh animal keeper PPS Alobi setiap setiap hari. Terakhir, aspek manajemen kesehatan dimana PPS Alobi memiliki dokter hewan stand by yang akan memeriksa kondisi satwa saat diselamatkan, memberikan perawatan, kemudian pengecekan kesehatan rutin, dan pemberian vitamin atau suplemen setiap bulan.
Selain Mentilin (Cephalopacus bancanus), PPS Alobi juga menyelamatkan hewan endemik Bangka lainnya yaitu Kukang Bangka / Bangka Slow Loris (Nycticebus bancanus). Kesejahteraan hewan (Animal Welfare) Kukang di PPS Alobi ini juga sudah pernah diteliti oleh mahasiswa dari Universitas Sriwijaya untuk tugas akhir skripsinya. Berdasarkan lima aspek pengelolaan, kesejahteraan hewan Kukang Bangka di PPS Alobi dinilai baik (Situmorang 2021). Jadi, bagi akademisi yang mau meneliti Mentilin atau Kukang Bangka, PPS Alobi dengan senang hati meyambut. Tentang Kukang Bangka, kita bahas lebih banyak di artikel selanjutnya ya. Tetap penasaran!
Daftar Pustaka:
Arrijani, Rizki M.2020. Vegetation analysis and population of tarsier (Tarsius spectrumgurskyae) at Batuputih Nature Tourism Park, North Sulawesi, Indonesia. Biodiversitas 20(2):530-537. https://doi.org/10.13057/biodiv/d210214.
Dalimunthe NP, Syafutra R, Priyansah S. Maintenance Management Of Mentilin (Cephalophacus bancanus bancanus) In Captivity In Alobi PPS As A Means Of Exsitu Conservation. International Journal of Science and Environment 4(2):58–64. https://doi.org/10.51601/ijse.v4i2.95.
Gursky SD.2013. Acoustic characterization of ultrasonic vocalizations by a nocturnal primate Tarsius syrichta.Primates 54(3):293-299. https://doi.org/10.1007/s10329-013-0349-3.
Madhusudhana, S. et al.2022. Choosing Equipment for Animal Bioacoustic Research. In: Erbe, C., Thomas, J.A. (eds) Exploring Animal Behavior Through Sound: Volume 1. Springer, Cham. https://doi.org/10.1007/978-3-030-97540-1_2.
Situmorang FKB.2021.Kajian kesejahteraan kukang Bangka (Nycticebus bancanus) pada lembaga konservasi khusus di Pusat Penyelamatan Satwa (PPS) ALOBI Bangka Belitung [skripsi]. Palembang:Universitas Sriwijaya.
Yustian I, Kurniawan D, Effendi Z, Setiawan D, Patriono E, Hanum L, Setiawan A.2021. Vocalization of Western Tarsier (Cephalopachus bancanus Horsfield, 1821) in Bangka Island, Indonesia. Journal of Tropical Biodiversity and Biotechnology 6(3):1-10. https://doi.org/10.22146/jtbb.65526.
Penulis: Frista Chairunnisa | 19 Mei 2025
Editor: Langka Sani
Presumed Silent, Yet Western Tarsier Emits Sounds Beyond Human Hearing
Writer : Frista Chairunnisa | 19 May 2025
Editor: Langka Sani
Western Tarsier rarely makes a sound, even when we’re nearby. This animal tends to stay quiet, especially during the daytime. However, at night, Mentilin occasionally vocalizes, which makes sense, as nighttime is when this nocturnal primate is most active. Interestingly, Western Tarsier can also scream during the day if it feels panicked. For example, when it’s being handled by its animal keeper.
So, does this Bangka endemic species actually communicate with others of its kind? Let’s explore.
A study describing the vocalizations of Western Tarsier (Cephalopachus bancanus) was conducted by Yustian et al. (2021). They recorded Western Tarsier sounds from 5 p.m. to 7 a.m. over three consecutive nights. The study identified seven distinct vocalization types.
Among them was a “squeak” sound made exclusively by infant Mentilin (Figure 1), along with whistling and chirping sounds produced by both infants and adults. The remaining four vocalization types were made only by adult Mentilin.
It is believed that the shared vocalizations between infants and adults serve as a form of communication, possibly a way for infants to interact with their mothers.
There is also an agonistic scream that can reach ultrasonic levels (exceeding 20,000 Hz), typically occurring when two male individuals come into contact (Figure 2). This is understandable, as the Bangka Mentilin is a solitary and territorial animal. This behavior contrasts with that of its close relatives, the tarsiers from North Sulawesi which tend to live in small social groups of 2 to 8 individuals (Arrijani & Rizki, 2020).
Meanwhile, an even louder scream was recorded when a Western Tarsier felt panicked while being held or captured. This vocalization was identified by Yustian (2021) as a distress call and hysteresis, the latter referring to a prolonged stress effect. This can be observed in the spectrogram that has thick and high-pitched waveform patterns (Figure 3).
From the seven types of vocalizations described, we can conclude that Western Tarsier produces sounds that are still audible to the human ear. According to Yustian (2021), ultrasonic sounds were only detected when they occurred alongside audible screams. Starting at a frequency we could hear, and then extending into the ultrasonic range.
However, in a study by Gursky et al. (2013) on Western Tarsier’s close relative from the Philippines, Tarsius syrichta (now renamed Carlito syrichta, remember we mentioned this in a previous article!) recorded as many as 10,309 ultrasonic vocalizations. These recordings were collected over the course of three months and categorized by Gursky into three types of calls: chirps, twitters, and whistles.
Gursky herself noted that this was a preliminary study, and so the functions of these ultrasonic vocalizations remain speculative. One hypothesis is that they serve as a form of acoustic camouflage which allowing tarsiers to communicate with one another without alerting predators to their presence. Interestingly, Gursky reported that she and her field assistant witnessed tarsiers opening their mouths, but no sound could be heard!
In her discussion, Gursky also raised the possibility that these inaudible vocalizations could be used to distinguish between different tarsier species. A truly fascinating idea. Why? Because it reflects just how far the fields of ecology and conservation have progressed.
Today, to analyze environmental conditions, researchers can simply record the sounds of a habitat. This approach is known as bioacoustic monitoring, a method used to assess the presence, distribution, and behavior of wildlife in nature. It has become a highly effective and innovative tool in monitoring animals, especially those that have been rehabilitated and released into the wild.
Not only does bioacoustic monitoring speed up the identification and tracking process without the need for intensive field exploration, but it is also non-invasive, meaning it causes no stress or disturbance to the animals. Even without direct interaction, researchers can gather valuable data to understand the population dynamics and distribution of species in their natural habitats.
However, to get to that point, further research is essential, particularly to understand the vocalization system of Western Tarsier. Through such studies, we can identify specific sounds that may serve as indicators of stress or adaptation of Western Tarsier in the environment.
So, anyone interested in conducting research in this area?
The maintanance management of Western Tarsier at the Alobi Wildlife Rescue Center (PPS Alobi) has been evaluated positively based on several key management aspects, according to a study by Dalimunthe et al. (2024) from Universitas Muhammadiyah, Bangka Belitung.
Several aspects were evaluated in the study, including the enclosure design, which follows an outdoor model built to closely mimic Western Tarsier’s natural habitat. Complete with branches and tree branch for climbing.
Feeding practices are also well adjusted, where Bangka Western Tarsiers being provided with crickets, grasshoppers, and occasionally german caterpillars. Food and drinking water are given and replaced daily by the animal keepers at PPS Alobi.
Lastly, in terms of health management, PPS Alobi has an on-call veterinarian responsible for conducting health checks upon arrival, providing medical care when needed, and performing routine monthly check-ups, including the administration of vitamins and supplements.
In addition to Western Tarsier (Cephalopachus bancanus), PPS Alobi also rescues another Bangka endemic species, the Bangka Slow Loris (Nycticebus bancanus). The animal welfare of the Slow Loris at PPS Alobi has also been studied by a student from Sriwijaya University as part of their undergraduate thesis. Based on five management aspects, the welfare of Bangka Slow Lorises at PPS Alobi was assessed to be in good condition (Situmorang, 2021).
So, for academics or researchers interested in studying Western Tarsier or Bangka Slow Lorises, PPS Alobi warmly welcomes your research initiatives!
As for the Slow Loris, we’ll dive deeper into that in the next article. Stay curious!
Daftar Pustaka:
Arrijani, Rizki M.2020. Vegetation analysis and population of tarsier (Tarsius spectrumgurskyae) at Batuputih Nature Tourism Park, North Sulawesi, Indonesia. Biodiversitas 20(2):530-537. https://doi.org/10.13057/biodiv/d210214.
Dalimunthe NP, Syafutra R, Priyansah S. Maintenance Management Of Mentilin (Cephalophacus bancanus bancanus) In Captivity In Alobi PPS As A Means Of Exsitu Conservation. International Journal of Science and Environment 4(2):58–64. https://doi.org/10.51601/ijse.v4i2.95.
Gursky SD.2013. Acoustic characterization of ultrasonic vocalizations by a nocturnal primate Tarsius syrichta.Primates 54(3):293-299. https://doi.org/10.1007/s10329-013-0349-3.
Madhusudhana, S. et al.2022. Choosing Equipment for Animal Bioacoustic Research. In: Erbe, C., Thomas, J.A. (eds) Exploring Animal Behavior Through Sound: Volume 1. Springer, Cham. https://doi.org/10.1007/978-3-030-97540-1_2.
Situmorang FKB.2021.Kajian kesejahteraan kukang Bangka (Nycticebus bancanus) pada lembaga konservasi khusus di Pusat Penyelamatan Satwa (PPS) ALOBI Bangka Belitung [skripsi]. Palembang:Universitas Sriwijaya.
Yustian I, Kurniawan D, Effendi Z, Setiawan D, Patriono E, Hanum L, Setiawan A.2021. Vocalization of Western Tarsier (Cephalopachus bancanus Horsfield, 1821) in Bangka Island, Indonesia. Journal of Tropical Biodiversity and Biotechnology 6(3):1-10. https://doi.org/10.22146/jtbb.65526.
