Predation Experiments on Infant Spectral Tarsiers (Tarsius spectrum)

Abstract

In this paper, I investigate how mother and infant spectral tarsiers, Tarsius spectrum, respond to the presence of potential predators. I conducted this study at Tangkoko Nature Reserve in Sulawesi, Indonesia, from June to November 1999. I exposed 2 infants to 3 types of potential predators (large models of birds of prey, large rubber snakes and the vocalizations of large birds of prey) for a total of 18 nights. Infants moved a greater distance from their parked location when exposed to rubber snakes (1.8 m) compared to nights when they were not exposed to potential predators (0.23 m). On the other hand, when large bird of prey models were placed near the parked infant, the infant did not move from its parked locale (0.05 m). Parked infants repeatedly gave alarm calls in response to the presentation of all potential predator types. When an infant produced an alarm call following the presentation of a potential predator, the mother responded with her own alarm call approximately 88% of the time. However, when an infant produced an inappropriate alarm call, the mother responded with her own alarm call only 19% of the time. These results suggest that spectral tarsier infants use alarm calls to ask questions about the things they encounter in their environment. Infants and mothers both produced a twittering alarm call in response to the bird of prey models, whereas they both produced a harsh loud call 3 times in rapid succession in response to the presence of the rubber snakes.

Why Mob? Reassessing the Costs and Benefits of Primate Predator Harassment

“…The fact that infant tarsiers less than a week old alarm-called in response to snakes, even if they had never encountered them before provides further evidence against this cultural transmission hypothesis [Gursky, 2003[Gursky, , 2006. Gursky [2006] also argues that her results -specifically the fact that the extragroup males recruited to mobbing events are not bigger than resident males -provide evidence against the 'attract the mightier' hypothesis.…”

“…Both observational and experimental studies of snake mobbing have been used to provide insight into the function of predator harassment in spectral tarsiers [Gursky, 2002[Gursky, , 2003[Gursky, , 2005[Gursky, , 2006[Gursky, , 2007. Gursky [2006] found that tarsiers did not always mob the snakes they encountered; mobbing was observed in only 11 of 43 encounters with real snakes (25%) and in 31 of 73 encounters (42%) with model snakes.…”

Ultrasonic Vocalizations by the Spectral Tarsier, Tarsius spectrum

“…They give early-morning family choruses, scentmark preferentially along the boundaries of their territory and regularly engage in territorial disputes with neighboring groups. Consequently, they exhibit minimal overlap between neighboring territories [Gursky, 2003]. Spectral tarsier home ranges vary from 1.6 to 4.1 ha with an average of 2.3 ha for females and 3.1 ha for males [Gursky, 2003].…”

“…Consequently, they exhibit minimal overlap between neighboring territories [Gursky, 2003]. Spectral tarsier home ranges vary from 1.6 to 4.1 ha with an average of 2.3 ha for females and 3.1 ha for males [Gursky, 2003]. Spectral tarsiers also exhibit a tremendous amount of site fidelity.…”

Infant Response to Mother Call Patterns in Otolemur garnettii

“…In their work, Cheney and Seyfarth [Cheney and Seyfarth, 1996;Seyfarth and Cheney, 1997] show that call referents and behavioral contingencies appear important for successful communication (see also Gursky [2003] for mother-infant calls in spectral tarsiers). The current work employs quantitative techniques suited to (1) identification of patterns or sequences of behavior of an individual and (2) testing of whether those patterns are important predictors of behavioral outcomes of another individual [Gottman and Bakeman, 1979;Bakeman and Quera, 1995;Bakeman and Gottman, 1997].…”