The metacommunication hypothesis asserts that some elements of play behaviour are associated with play elements borrowed from aggression and interpret these aggression-like elements as playful. Using data from free living Hanuman langurs (Semnopithecus entellus), we tested three predictions that follow from the metacommunication hypothesis: (i) aggression-like elements (ALEs) abbreviate play bouts; (ii) candidate signal elements are sequentially associated with ALEs; (iii) associations of candidate signal elements with ALEs prolong play bouts. Play face and five other candidate signal elements were evaluated in relation to nine ALEs. We confirmed all three predictions for play face, albeit only if the play face and/or the ALEs occurred at the start of the play bout. The other candidate elements were not associated with ALEs. We conclude that play face fulfils the metacommunicatory function in Hanuman langur play bouts, while other play specific elements may serve other signal or non-signal functions.

In this paper, I present the first observations on the ontogeny of tarsier infants during their first and second months and of the mother-offspring bond from birth until separation. Tarsier mother-infant pairs were observed to be solitary. Maternal care involved a cache and carry strategy with the infant spending around 66% parked alone whilst the mother was foraging. I observed the following behaviour: rest, grooming, suckling, play, being carried, jumping and climbing. Percentage of time spent in each activity was calculated. Furthermore, play was observed to include locomotor-, social-and object-directed behaviours. Acoustic communication between mother and infant was very frequent containing four different signals. During the first days after birth, the mother transported the infants about, but within a week, the infants started climbing branches on their own. For the first three weeks, the mothers carried infants orally after which they started to follow the mother over shorter distances, although for longer distances, up to 50 days of age, the mothers continued to carry them. The inter-birth interval was around 1 year, but the infants from the previous birth continued to sleep with the mother for up to 10 months.

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Among tarsiers, nocturnal, obligatory faunivorous primates inhabiting islands of South-East Asia, the Philippine tarsier (Tarsius [= Carlito] syrichta) is one of the least studied. To date, activity patterns of this threatened species have not been the subject of any investigation. In the present study, we provide the first quantitative data on how captive male and female T. syrichta apportion their time for various activities in two social contexts: solitary and paired. We found that the sexes do not differ in activity budgets during the non-mating season, both spending most of their time scanning, resting, foraging and travelling. Comparison of activity budgets of the sexes between the mating and non-mating seasons revealed that although both tarsiers noticeably increased travelling time at the expense of time spent resting, the male changed his behaviour to a much greater extent than the female. We also report on fluctuations in the tarsiers’ activities throughout a night and compare time budgets of T. syrichta with available data on the western and eastern species of tarsiers. The results extend the current knowledge of tarsier behaviour and may also assist in practical considerations for keeping this highly sensitive, difficult-to-breed species in captivity.