Tarsius

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Clink et al. (2020) [web] Abstract: Duetting, or the stereotypical, repeated and often coordinated vocalizations between 2 individuals arose independently multiple times in the Order Primates. Across primate species, there exists substantial variation in terms of timing, degree of overlap, and sex-specificity of duet contributions. There is increasing evidence that primates can modify the timing of their duet contributions relative to their partner, and this vocal flexibility may have been an important precursor to the evolution of human language. Here, we present the results of a fine-scale analysis of Gursky’s spectral tarsier Tarsius spectrumgurskyae duet phrases recorded in North Sulawesi, Indonesia. Specifically, we aimed to investigate individual-level variation in the female and male contributions to the duet, quantify individual- and pair-level differences in duet timing, and measure temporal precision of duetting individuals relative to their partner. We were able to classify female duet phrases to the correct individual with an 80% accuracy using support vector machines, whereas our classification accuracy for males was lower at 64%. Females were more variable than males in terms of timing between notes. All tarsier phrases exhibited some degree of overlap between callers, and tarsiers exhibited high temporal precision in their note output relative to their partners. We provide evidence that duetting tarsier individuals can modify their note output relative to their duetting partner, and these results support the idea that flexibility in vocal exchanges—a precursor to human language—evolved early in the primate lineage and long before the emergence of modern humans.

Indrawan et al. 2022. [WEB]. Reference Module in Earth Systems and Environmental Sciences. ISBN 9780124095489. Abstract: Tarsius pelengensis is one of 11 known tarsier species from Sulawesi. Peleng tarsiers are a poorly known species endemic to Peleng Island, Sulawesi region and are believed to be Endangered. Here we present this species’ taxonomy, morphology, vocal description, distribution, habitat, and basic natural history. The Peleng tarsier is relatively large, with dark skin and pelage, and emits duets calls that differ from all other known tarsiers except for T. dianae. Peleng tarsiers are found only on two islands, namely Peleng and Banggai. They are distributed across all vegetated habitats from the lowlands to the highest elevational range (c. 1000m. asl). The limestone island of Peleng is covered by moist forest habitats. The Peleng tarsier is both nocturnal and arboreal. Detailed field observations indicates that they travel in small parties, probably family groups, of up to eight individuals. Additional observations suggests that this species breeds once a year, prior to the rainy season, and produces a single offspring. Although classified as Endangered, this tarsier species is locally abundant throughout Peleng. Given this new data, this species’ conservation status may need to be reevaluated. We also highlighted the progression of 15years of voluntary conservation effort, led by Indrawan.

Zakaria et al. xxxx. [Web] Studi kami berfokus pada lengan utara yang panjang dari Sulawesi, yang menjadi rumah bagi tiga spesies tarsius yang dikenal: Tarsius spectrumgurskyae, T. supriatnai, dan T. wallacei. Lokasi tepat batas-batas tersebut tidak diketahui, tetapi hipotesis biogeografis untuk pulau tersebut menghasilkan prediksi mengenai di mana batas-batas tersebut akan berada. Kami menggunakan survei akustik untuk menemukan batas fauna tarsius dan zona kontak di sepanjang kedua pantai semenanjung utara. Kami menganalisis parameter duet dari 82 panggilan duet tarsius dari 49 lokasi. Hasil kami mengungkapkan empat kelompok akustik: Manado (T. spectrumgurskyae), Gorontalo (T. supriatnai), Tinombo (T. Wallacei), dan kelompok sebelumnya yang tidak diketahui antara Manado dan Gorontalo, yang kami sebut bentuk Labanu. Hasil kami di pantai selatan mengungkapkan batas fauna yang terkait dengan hambatan geografis. Di sepanjang pantai utara, batas fauna tidak terkait dengan hambatan geografis. Upaya survei intensif mengidentifikasi kelompok heterospesifik dalam satu spektrogram. Wilayah studi telah mengalami deforestasi signifikan, terutama wilayah di mana bentuk Labanu ditemukan. Kami curiga bentuk ini sebagai hibrida stabil yang terbentuk oleh kontak sekunder antara T. spectrumgurskyae dan T. supriatnai. Kami memperkirakan bahwa bentuk Labanu akan masuk daftar merah spesies terancam punah jika sudah ditentukan sebagai spesies baru. Penelitian genetik tindak lanjut sangat mendesak untuk memvalidasi status taksonomi bentuk akustik baru sebelum punah karena kehilangan habitat.

Gursky-Doyen,  S.. 2011. Infanticide by a male spectral tarsier (Tarsius spectrum) Primates, 52(4):385-9. DOI.  Web.  Abstract: As part of a long-term field study on the behavioral ecology and conservation of a population of spectral tarsiers (Tarsius spectrum) in Tangkoko Nature Reserve, Sulawesi, Indonesia, I observed the first known instance of infanticide in this species. A young infant was killed by a neighboring male. Neither the epiphenomenal aggression hypothesis, social pathology hypothesis, nutritive benefits of cannibalism hypothesis, nor sexual selection hypothesis are supported by this observation. The only hypothesis that could not be rejected outright, on the basis of this single observation, was the competition for limited resources hypothesis.

Gursky, S.. 2015. Ultrasonic Vocalizations by the Spectral Tarsier, Tarsius spectrum. Folia Primatologica, 86(3):153-63.  DOI. WEB. Abstract: Although the vocalizations of spectral tarsiers have been studied for over 3 decades by numerous primatologists, the data in this paper represent the first evidence that this species communicates in the ultrasonic range. In addition, this paper characterizes the types of ultrasonic vocalizations by spectral tarsiers, Tarsius spectrum. Data were collected at Tangkoko Nature Reserve in Sulawesi, Indonesia, from January through April 2013. Recordings were made on a Wildlife Acoustics Ultrasonic Song Meter BAT2 from 10 groups of varying sizes and compositions. The ultrasonic recorder was placed at the base of the group's sleeping tree and recorded from 5.00 to 7.00 h using an omnidirectional microphone. The ultrasonic vocalizations fell into 5 main categories: chirps, twitters, choruses, doubles and whistles. Chirps were the most frequent ultrasonic vocalizations, followed by twitters, choruses, doubles and then whistles. While chirps, twitters and choruses extended from the audible to the ultrasonic range, the doubles and whistles were pure ultrasound. Currently, the function of these ultrasonic vocalizations is not yet clear and requires additional research.

Gursky, S. 2019. Echolocation in a Nocturnal Primate? Folia Primatologica, 90(5):379-391.   DOI. WEB. Abstract: Recently it has been noted that Gursky's spectral tarsier emits ultrasonic calls. Because high-frequency sounds are capable of travelling only short distances, their function is limited by the distance the sound can be discerned. One possible function for these short-distance, high-frequency sounds is that they might be used by the tarsiers to navigate throughout their environment. I conducted this study at Tangkoko Nature Reserve in Sulawesi, Indonesia, from May to August 2017. Using the focal follows, I recorded the start of each locomotor activity to the nearest second. I also simultaneously recorded all ultrasonic vocalisations that the focal individual emitted using a Wildlife Acoustics Ultrasonic Song Meter BAT3. Approximately 42% of the ultrasonic calls that I recorded during this study were given within 1 s prior to engaging in locomotor activity. The tarsiers gave statistically more ultrasonic calls during locomotion than during other behaviours (rest, forage and social). Four types of ultrasonic calls were given while locomoting: whistles, doubles, trills and frequency-modulated calls. Of these, the trill and the frequency-modulated call were only given during locomotion, and trills were only given prior to leaping. These results preliminarily suggest that the tarsiers do use ultrasonic calls for navigation. Studying echolocation in organisms closely related to bats is critical for understanding the evolution of echolocation.

Gursky-Doyen, S.. 2013. Acoustic characterization of ultrasonic vocalizations by a nocturnal primate Tarsius syrichta. Primates, 54(3):293-9. DOI. WEB. Abstract: This preliminary study characterizes the ultrasonic vocalizations produced by Philippine tarsiers, Tarsius syrichta. Data were collected at the Philippine Tarsier Foundation Sanctuary in Corella, Bohol, Philippines, from July through October 2010. Recordings were made on a Wildlife Acoustics Ultrasonic Song Meter 2 BAT from 29 wild, free-living adult resident T. syrichta (23 females and six males). A total of 10,309 USVs were recorded. These vocalizations fell into three main categories: chirps, twitters, and whistles. Chirps were the most frequent, followed by twitters and whistles. Whereas chirps and twitters were emitted by both male and female Philippine tarsiers, whistles were only emitted by adult males. Given that vocalizations reported in this study were exclusively recorded during capture and handling, it is very likely that these vocalizations function as distress calls. However, as the long whistle was only given by adult males who were captured at the same time as the female or the group's infant, the function of the long whistle might be slightly different than the function of the other relatively lower-frequency USVs.

MacKinnon, J., & K. MacKinnon. 1980. The behavior of wild spectral tarsiers. International Journal of Primatology, 1:361–379. WEB.  Abstract: Field data are presented from a 15-month study of spectral tarsiers in North Sulawesi, Indonesia, based on over 300 sightings of animals in the wild and supplemented by observations from other parts of the island. Animals in study area were caught in mist nets and marked with colored plastic bird rings so that tarsiers followed at night could be individually recognized. Ecological data presented cover the locomotion, use of forest strata, and diet of tarsiers. Although clearly specialized for vertical clinging and leaping, the spectral tarsier is less specialized than the western tarsier, occupying a wider range of habitats and using a wider range of vegetation strata and locomotor patterns. Diet is mostly insects collected both on the ground and in trees. Spectral tarsiers were found to be monogamous and territorial. Families regularly slept at the same sites each day and gave loud duet songs as they congregated at sleeping sites each dawn. Sometimes similar songs were given in the night during territorial conflicts. Family home ranges were plotted and average about 1 ha. Observations are included on mating, the development of young tarsiers, and the dispersion of juveniles. Tarsier young are very precocious and may travel independently as little as 23 days after birth. Tarsiers regularly scent marked their ranges by rubbing branches with urine and special epigastric glands. In addition, they have a varied repertoire of calls and the main vocalizations are described.

Brandon-Jones, D., A.A. Eudey, T. Geissmann, C.P. Groves, D.J. Melnick, J.C. Morales, M. Shekelle & C.-B. Stewart. 2004. Asian primate classification. International Journal of Primatology, 25(1): 97–164. [WEB]

Nietsch, A., & C. Niemitz. 1993. Diversity of Sulawesi tarsiers. Deutsche Gesellschaft Fur Saugetierkunde, 67, 45–46. Google Scholar 

Nietsch, A., & M.L. Kopp. 1998. Role of vocalization in species differentiation of Sulawesi tarsiers. Folia Primatologica, 69(SUPPL. 1):371–378. DOI. Article Google Scholar 

Nietsch, A. (1999). Duet vocalizations among different populations of Sulawesi tarsiers. International Journal of Primatology, 20(4): 567–583. DOI

Hagemann, L., N. Grow, Y.E-M. B. Bohr, D. Perwitasari-Farajallah, Y. Duma, S.L. Gursky, S. Merker. 2022. Small, odd and old: The mysterious Tarsius pumilus is the most basal Sulawesi tarsier. Biology Letter. 18(3):20210642.  [DOI] [PMC article]. Abstract: In this study, we present the first genetic evidence of the phylogenetic position of Tarsius pumilus, the mountain tarsier of Sulawesi, Indonesia. This mysterious primate is the only Eastern tarsier species that occurs exclusively in cloud forests above 1800 m.a.s.l. It exhibits striking morphological peculiarities-most prominently its extremely reduced body size, which led to the common name of 'pygmy tarsier'. However, our results indicate that T. pumilus is not an aberrant form of a lowland tarsier, but in fact, the most basal of all Sulawesi tarsiers. Applying a Bayesian multi-locus coalescent approach, we dated the divergence between the T. pumilus lineage and the ancestor of all other extant Sulawesi tarsiers to 9.88 Mya. This is as deep as the split between the two other tarsier genera Carlito (Philippine tarsiers) and Cephalopachus (Western tarsiers), and predates further tarsier diversification on Sulawesi by around 7 Myr. The date coincides with the deepening of the marine environment between eastern and western Sulawesi, which likely led to allopatric speciation between T. pumilus or its predecessor in the west and the ancestor of all other Sulawesi tarsiers in the east. As the split preceded the emergence of permanent mountains in western Sulawesi, it is unlikely that the shift to montane habitat has driven the formation of the T. pumilus lineage.

 Sumampow TCP, Shekelle M, Beier P, Walker FM, Hepp CM. 2020. Identifying genetic relationships among tarsier populations in the islands of Bunaken National Park and mainland Sulawesi. PLoS One. 2020 Mar 26;15(3):e0230014. doi: 10.1371/journal.pone.0230014. eCollection 2020. [PCM Article PDF] [Plos One PDF]. Abstract: Eastern tarsiers (Tarsius tarsier complex) are small nocturnal primates endemic to Sulawesi Island and small adjacent islands of Indonesia. In 2004, the hybrid biogeography hypothesis predicted this species complex might contain 16 or more taxa, each corresponding to a region of endemism, based on: 1) geological evidence of the development of the archipelago, 2) biological evidence in the form of concordant distributions of monkeys and toads, and 3) the distribution of tarsier acoustic groups. Since then, 11 tarsier species have been recognized, potentially leaving more to be described. Efforts to identify these cryptic species are urgently needed so that habitat conversion, pet trade, and cultural activities will not render some species extinct before they are recognized. We gathered data to test the hypothesis of cryptic tarsier species on three volcanic islands in Bunaken National Park, North Sulawesi, namely Bunaken, Manadotua, and Mantehage, during May-August 2018. We sequenced individuals at 5 nuclear genes (ABCA1, ADORA3, AXIN1, RAG, and TTR) and made comparisons to existing genotypes at 14 mainland sites. Bayesian phylogenetic analyses revealed that island populations are genetically identical in all 5 genes, and formed a clade separated from the mainland ones. The eastern tarsiers first diverged from the western tarsiers approximately 2.5 MYA. The three island populations diverged from mainland tarsiers approximately 2,000–150,000 YA, due to either human activities or natural rafting. This study provides information for tarsier conservation, advances the understanding of biogeography of Sulawesi, and contributes to Indonesian awareness of biodiversity. Further quantitative genetics research on tarsiers, especially the island populations, will offer significant insights to establish more efficient and strategic tarsier conservation actions.

Driller C, Merker S, Perwitasari-Farajallah D, Sinaga W, Anggraeni N, Zischler H. 2015. Stop and Go - Waves of Tarsier Dispersal Mirror the Genesis of Sulawesi Island. PLoS One. 2015 Nov 11;10(11):e0141212. doi: 10.1371/journal.pone.0141212. eCollection 2015. [PCM Article PDF] [Plos One PDF. Abstract: The Indonesian island of Sulawesi harbors a highly endemic and diverse fauna sparking fascination since long before Wallace’s contemplation of biogeographical patterns in the region. Allopatric diversification driven by geological or climatic processes has been identified as the main mechanism shaping present faunal distribution on the island. There is both consensus and conflict among range patterns of terrestrial species pointing to the different effects of vicariant events on once co-distributed taxa. Tarsiers, small nocturnal primates with possible evidence of an Eocene fossil record on the Asian mainland, are at present exclusively found in insular Southeast Asia. Sulawesi is hotspot of tarsier diversity, whereby island colonization and subsequent radiation of this old endemic primate lineage remained largely enigmatic. To resolve the phylogeographic history of Sulawesi tarsiers we analyzed an island-wide sample for a set of five approved autosomal phylogenetic markers (ABCA1, ADORA3, AXIN1, RAG1, and TTR) and the paternally inherited SRY gene. We constructed ML and Bayesian phylogenetic trees and estimated divergence times between tarsier populations. We found that their arrival at the Proto-Sulawesi archipelago coincided with initial Miocene tectonic uplift and hypothesize that tarsiers dispersed over the region in distinct waves. Intra-island diversification was spurred by land emergence and a rapid succession of glacial cycles during the Plio-Pleistocene. Some tarsier range boundaries concur with spatial limits in other taxa backing the notion of centers of faunal endemism on Sulawesi. This congruence, however, has partially been superimposed by taxon-specific dispersal patterns.

Gursky, S..  2000. Sociality in the spectral tarsier, Tarsius spectrum.  American Journal of Primatology 51(1):89-101. DOI. Abstract: Recent studies indicate that many of the nocturnal prosimian primates are gregarious rather than solitary. This paper shows that the spectral tarsier is gregarious during its nightly activity period as well as in its sleeping tree. Using mist nets and radiotelemetry, focal follows were conducted on six groups at Tangkoko Nature Reserve in Sulawesi, Indonesia. During 442 focal follows, 1072 encounters between a focal adult group member and another adult were observed. The number of encounters ranged from as few as 0 to as many as 18 encounters per night. Intragroup encounters lasted from less than 1 min to as long as 3 hr 12 min. Nearly one-half of all social behavior occurred between adult females and males. There were also substantial rates of social interaction between the two adult females in one group, and between sub-adults of the opposite sex in neighboring groups.

Gursky, S.. 2005. Predator Mobbing in Tarsius spectrum. International Journal of Primatology 26(1):207-221. DOI

Gursky, S.. 2002. Determinants of gregariousness in the spectral tarsier (Prosimian: Tarsius spectrum). Journal of Zoology 256(3). DOI

Sarang Tangkoko Tarsius nest https://maps.app.goo.gl/gHJXG511eCZRZPxo9