Predation on a wild Philippine tarsier (Tarsius syrichta)

Little is known about predation on the Philippine tarsier. Only one other case of predation, probably by a cat, has previously been reported. In our study, we present two events of predation, one on a female tarsier by a water monitor lizard, another on an infant tarsier by an unknown predator. We also describe the behaviour of the tarsier mother after losing her infant. Our observations extend current knowledge about predation pressure on the Philippine tarsier.     

Successful breeding attempt of a pair of Philippine tarsier (Tarsius syrichta) in a conservation center in Bilar,Bohol, Philippines and recommendations for tarsier husbandry

The Philippine tarsier (Tarsius syrichta) belongs to the least known nocturnal primates. Tarsiers and remaining biodiversity of the Philippines are under tremendous threats from increasing human expansion, with habitat loss and illegal pet trade being the main reasons for tarsier population decline. In addition, even though the attempts were made by western and local facilities, tarsiers have not survived well in captivity. In this paper, I present an example of successful breeding of the Philippine tarsier in captive conditions but in natural climate. As the most important elements of success, I see a large amount of space provided to tarsiers, the climate similar to their natural habitat and the food resembling their natural diet. Our pair of tarsiers were joined during the mating period and held separately outside the mating period, which corresponds with their behavior in the wild and may have played a crucial role in breeding success. Eliminating stress to animals is also important. The study can provide valuable guidelines for other facilities keeping tarsiers in the Philippines and help to improve tarsiers’ welfare and in the future help to establish a viable captive population of the Philippine tarsier that will serve as a backup population and also will decrease demand on tarsiers captured from the wild.     

Hand-raising a philippine tarsier,Tarsius syrichta

An infant female tarsier (Tarsius syrichta) weighing 20 g at birth was removed for hand-raising at 1 day of age. The infant was maintained in an incubator (32°C, 80% humidity), and fed every 2–3 hours for the first 10 days of life. The infant received a varied formula for the first 4 days. Esbilac (3.3–8.0 cc daily) was given for days 5–10. From days 11 to 67 the infant was fed 6.5–8.0 cc of formula seven times daily. A liver fortified formula was introduced on day 53. Birthweight doubled by day 41 and tripled by day 101. The animals first successful jump was observed at day 25. On day 68 she captured and ate her first live prey. Introduction to adult tarsiers began on day 60. This is the first successful hand-raising of any species of tarsier, which is a genus that reproduces poorly in captivity.     

Introducing an innovative semi‐captive environment for the Philippine tarsier (Tarsius syrichta)

In response to demands for research, captive breeding, and tourism, a semi‐captive environment was created for the Philippine tarsiers (Tarsius syrichta) in Corella, Bohol, Philippines. The 7600‐m² enclosure was continuous with the surrounding habitat, and utilized a unique predator control fence design and a lighting system to attract nocturnal insects. During 2 years of observation, the locations of over 500 tarsier sleeping sites were recorded. Tarsiers were found to prefer dense, low‐level vegetation in secondary forests, with perching sites averaging 2 m above the ground. Up to 10 tarsiers were observed within the enclosure at one time, which is a high density compared to densities based on home‐range estimates for wild tarsiers in the vicinity of the study site. In addition, the tarsiers were observed to be more social than previously reported. Zoo Biol 24:101–109, 2005. © 2005 Wiley‐Liss, Inc.     

The skin of primates. XLIII. Further observations on the Philippine tarsier (Tarsius syrichta)

Underneath the volar friction surfaces is a highly developed, anastomosing system of alkaline phosphatase-reactive capillaries; numerous cholinesterase-positive hederiform nerve end-organs are present in the scalp, forehead, lower abdomen, back, and perianal region; sinus hair follicles occur on the flexor surface of the antebrachium; and a dense field of gigantic sebaceous and admixed apocrine glands constitutes the epigastric gland.     

Positional behavior and social organization of the philippine tarsier (Tarsius syrichta)

This study provides preliminary data on the positional behavior and habitat use of the Philippine tarsier,Tarsius syrichta, which was studied in its natural habitat on the island of Leyte. The locomotor behavior ofT. syrichta is quite comparable to the other species of tarsiers but frequency of use of different postures and support types does seem to distinguish this species from the others.Tarsius bancanus appears to be the most specialized, using vertical clinging postures the most frequently and sitting the least;Tarsius dianae uses vertical clinging the least frequently and sitting the most, andT. syrichta is intermediate. The Philippine tarsier has a small home range similar to that ofT. spectrum. On the other hand, this species likely does not have the small family groups typical of Sulawesi tarsiers but instead uses a noyau system likeT. bancanus. This data supports some apsects ofNiemitz’s (1977) model of anatomical and behavioral specialization among tarsier species.     

Sociality in the spectral tarsier, Tarsius spectrum

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.     

Infant care in the spectral tarsier (Tarsius spectrum) Sulawesi,Indonesia

I present quantitative and qualitative data on infant caretaking behaviors collected during a preliminary field study of spectral tarsiers (Tarsius spectrum),in a northern Sulawesi rain forest. The primary goal of the study is to identify the basic pattern of infant care in this species. I studied tarsiers at Tangkoko-Dua Saudara Nature Reserve in Sulawesi, Indonesia, from May to July 1992. I observed two infants, from two groups for a total of 96 hr using focal follows. During individual focal follows, ranging from 20 min to 6 hr, I recorded behaviors at 5-min intervals. I also recorded distances of group members relative to the infant at 5-min intervals. I subsampled the data at 35-min intervals to control for statistical autocorrelation between data points. Infants were alone between 40 and 50% of the time. The two subadults were more frequently in proximity to the infant than the adult males, the nonmatemal adult female, or the mothers were. This pattern of the subadults maintaining proximity to the infant continued when the mothers were absent. These results suggest that subadults may be guarding or babysitting infants. It is also possible that subadults are not traveling as far from the sleeping site as adults do and are therefore more likely to be found in association with the infant.     

Hand‐raising a spectral tarsier (Tarsius tarsier) at the Ueno Zoological Gardens

On February 10, 2008, a newborn male spectral tarsier (Tarsius tarsier) was found on the floor of the indoor exhibit room in the Small Mammal House of the Ueno Zoological Gardens. The dam showed no signs of providing maternal care and therefore we decided to hand‐raise the infant. Its birth weight was 18.7 g. We placed the dam and infant in an incubator and gave 12.5–25% formula (for kittens), until the 145th day after birth. We limited the volume of formula intake to avoid excessive intake and to prevent diarrhea. For nutrition enrichment, we added a chicken liver homogenate to the formula 1–3 times per day. The infant was given a sunbath for 10 min on the 28th day. He showed no serious decline in health, except for diarrhea that occurred during the first few days after birth. He ate a small cricket for the first time on the 50th day and easily caught mealworms on his own on the 105th day. Gradual changes in feeding times, formula concentration, and the nutritionally enriched formula were essential for successfully hand‐raising the tarsier. Zoo Biol 30:218–224, 2011. © 2010 Wiley‐Liss, Inc.     

Feeding behavior,mastication, and tooth wear in the western tarsier (Tarsius bancanus)

We assessed feeding and masticatory function in western tarsiers, Tarsius bancanus,from field study, from videotaped recordings of the feeding and chewing behavior of wild-caught animals in temporary captivity, from dissections of the muscles of mastication, and from scanning electron microscopic (SEM) examination of wear features of the teeth. Ingestion of large items of animal prey is made possible by the animal’s extremely wide gape. Anterior translation of the knob-like mandibular condyle in the anteroposteriorly elongated mandibular fossa makes possible a gape angle of 60–70‡. We observed two means of ingestion of grasshopper prey: ingestion by mastication, in which the postcanine teeth sever and reduce bites of the food as it is thrust into the mouth cavity, and repeated gape-shove sequences, during which the tarsier pushed grasshoppers of large diameter into the anterior part of its mouth and attempted to sever a bite with its anterior teeth. Morsels were successfully severed after three to five such sequences, and reduced quickly,with relatively few powerful, crushing chews. The insect cuticle was not evenly comminuted during mastication. We observed a marked side-to-side grinding component in the normal chewing cycle of T. bancanuson videotape and confirmed it by SEM. The main jaw adductors are bulky, long-fibered muscles that can accommodate wide grapes and still generate, at wide degrees of gape,the high occlusal pressures necessary to fracture thick chitinous exoskeletons of the scarabid beetles that form a substantial element of the western tarsier’s diet.     

Allocare in a nocturnal primate: data on the spectral tarsier, Tarsius spectrum

Non-maternal infant care in many of the small-bodied New World primate species has been hypothesized by some researchers to be related to the high infant/adult weight ratio found in these species. The spectral tarsier, Tarsius spectrum, an Old World primate, has one of the highest infant/adult weight ratios of any primate, with infants weighing between 20-33% of adult weight at birth. On the basis of the hypothesized relationship between allocare and the infant/adult weight ratio, it is predicted that the spectral tarsier will also exhibit extensive allocaretaking behaviour. The results of this study indicate that although spectral tarsiers show care by male and female subadults as well as adult males, it is extremely limited compared to the extensive allocaretaking behavior observed in New World primate species such as Aotus and Callicebus. Spectral tarsier subadult females provide substantially more allocare to infants than do subadult males or adult males. Female subadults were observed sharing food, transporting, grooming, playing, alarm calling, baby-sitting and maintaining physical contact with infants more than other age/sex classes. Although the amount of allocare exhibited by adult males and subadult males was much less than that exhibited by female subadults, the data suggest that adult and subadult male spectral tarsiers do play a small part in the care and socialization of the infant. Adult males and subadult males were both observed occasionally engaging in allocaretaking behaviors such as grooming and playing, as well as frequently patrolling and defending the territory's boundaries. The results from this study suggest that although a high infant/adult weight ratio may be a prerequisite for selection to favor extensive allocare, it is not a causal factor. Additional research is needed in order to understand better the selective pressures involved and the costs and benefits of providing allocare to subadults and adult male spectral tarsiers.     

Small,odd and old: The mysterious Tarsius pumilus is the most basal Sulawesi tarsier

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.