Preliminary Data on the Behavior, Ecology, and Morphology of Pygmy Tarsiers (Tarsius pumilus)

Abstract

We here present the first behavioral, morphological, and ecological data on a living group of highland pygmy tarsiers, Tarsius pumilus, and compare them with the lowland tarsier species of Sulawesi. Pygmy tarsiers were previously known only from 3 museum specimens and had not been seen alive since the first specimens were collected in 1917 and 1930. As part of a 2-mo exploratory study, we recently located a group consisting of ≥4 pygmy tarsiers in the mossy cloud forest of Lore Lindu National Park, Central Sulawesi, Indonesia. We captured 1 adult female and 2 adult male group members. The tarsiers weighed a mean of 50 g, less than half the weight of adult lowland tarsiers. Our behavioral observations indicate that these tarsiers live in small groups that return to the same sleeping tree each morning. Though our data are preliminary, pygmy tarsier body proportions appear to differ from the lowland Sulawesian tarsier species, with relatively long hind limbs compared to total body length. We also observed differences in grouping and communication behaviors. Unlike lowland tarsiers, pygmy tarsiers possess multiple adult males per group and rarely vocalize or scentmark. These differences may correlate with variables unique to their high altitude habitat, especially a reduction in food and tree resources, given that tree density declined sharply along an altitudinal gradient. Our preliminary study identifies the importance of altitudinal ecological gradients to tarsier behavioral ecology in Central Sulawesi, providing questions and predictions for future research directions.

Altitude and Forest Edges Influence the Density and Distribution of Pygmy Tarsiers (Tarsius pumilus)

“…Unlike all other tarsier species, pygmy tarsiers are thought to be restricted to highland mossy cloud forest on the island of Sulawesi, Indonesia [Musser & Dagosto, ]. Previously, the species was known only from three museum specimens independently collected in the years 1917, 1930, and 2000 [Maryanto & Yani, ; Musser & Dagosto, ; Shekelle, ], until 2008 when we observed a live population in Lore Lindu National Park [Grow & Gursky‐Doyen, ]. Initial observations suggested pygmy tarsiers differ from the lowland Sulawesian tarsier species in terms of behavior (larger groups and cryptic communication strategies), morphology (an extremely small body size with a mean body mass of 55 g, and relatively long hindlimbs), and an apparently low population density [Grow & Gursky‐Doyen, ].…”

“…Previously, the species was known only from three museum specimens independently collected in the years 1917, 1930, and 2000 [Maryanto & Yani, ; Musser & Dagosto, ; Shekelle, ], until 2008 when we observed a live population in Lore Lindu National Park [Grow & Gursky‐Doyen, ]. Initial observations suggested pygmy tarsiers differ from the lowland Sulawesian tarsier species in terms of behavior (larger groups and cryptic communication strategies), morphology (an extremely small body size with a mean body mass of 55 g, and relatively long hindlimbs), and an apparently low population density [Grow & Gursky‐Doyen, ]. Some have hypothesized that these unusual traits are related to their high‐altitude habitat [Grow & Gursky‐Doyen, ; Musser & Dagosto, ].…”

Altitudinal Distribution and Ranging Patterns of Pygmy Tarsiers (Tarsius pumilus)

“…They exhibit distinctive traits among tarsiers, including their anatomy (see Musser and Dagosto 1987) as well as cryptic behavior and communication (Grow and Gursky 2010). Until the first live observations of this species in 2008 (Grow and Gursky 2010), pygmy tarsiers were known only from three museum specimens, two of which were collected over 70 years ago: USNM 219454, found at 1,800 m at Rano Rano, AMNH 196477, found at 2,200 m at Latimojong, and MZB 22593, found at 2,200 m on Mt. Rore Katimbu (Maryanto and Yani 2004;Musser and Dagosto 1987).…”

Tarsius wallacei: A New Tarsier Species from Central Sulawesi Occupies a Discontinuous Range

“…Shekelle et al (1997, also in Shekelle 2003, 2008a reported results of field playback tests of Tarsius wallacei that unambiguously differentiated this species from T. dentatus, T. sangirensis, and as yet unnamed acoustic forms classified as T. tarsier, i.e., Manado, Gorontalo, Sejoli, and Togian forms. Indeed, differentiation of Tarsius wallacei from any known tarsier taxa other than the Togian form is trivial: 1) T. pumilus does not duet (Grow and Gursky-Doyen 2010;Shekelle 2008b).…”