Tactical deception in sociosexual behaviour of stump-tailed macaques (Macaca arctoides): an exploratory study

Tactical deception (TD) is a social strategy in which a subject performs an action to its own benefit causing disadvantage for a competitor. In primates, the cognitive mechanisms involved in TD have been described at different levels. Sneaky mating is a common context within which to study TD because in many primate groups, dominant males monopolize access to females and subordinate males must find a way to copulate with females avoiding the alpha’s presence. The objective of this study was to explore which of the TD behavioural strategies are involved in the male sociosexual behaviour of a group of stump-tailed macaques (Macaca arctoides). We found that the subordinate males participated in more interactions when they were in a section of the enclosure where the alpha male was not present. The alpha male had more copulation interactions, but the beta male’s interactions lasted longer on average. Our data offer evidence in support of the hypothesis that stump-tailed macaques may use TD strategies that are related to operant conditioning.

Dominance style predicts differences in food retrieval strategies

In several species, rank predicts access to food, and subordinates may need specific behavioural strategies to get a share of resources. This may be especially important in despotic species, where resources are strongly biased in favour of dominants and subordinates may more strongly rely on specific tactics to maximize food intake. Here, we compared three macaque species with an experimental set-up reproducing feeding competition contest. Following our predictions, more tolerant species mostly retrieved food in the presence of others and were less dependent on specific tactics. Contrarily, subordinates in more despotic species more likely collected food (1) when dominants could not see food or (2) were attacking others, (3) while “dissimulating”, or (4) “storing food”. Our study reveals that dominance styles reliably predict the probability of using specific food retrieval tactics and provides important insights on the social conditions that might have led to the emergence of tactical deception.

Alternative mating tactics and tactical deception: Is the common cuttlefish (Sepia officinalis) nothing but a common cheat?

Alternative mating tactics (AMTs) are common in the animal kingdom, yet much work remains before their evolution and role in driving sexual selection is fully understood. Utilizing features of citizen science, we present compelling evidence that a third species in the cuttlefish genusSepia(Cephalopoda) possess males who use sneaky mating and female mimicry as alternative strategies to conspicuous signalling and fighting. We also present new evidence of large aggregations (n~30) in this species that possibly drive alternative mating strategies. Lastly, we provide footage of an opportunistic sneaky copulation in this species. We believe that alternative mating tactics may be more common in this genus than previously recorded (based on observations presented here and a search of the literature for similar life history, environmental and behavioural factors found in other species within theSepiagenus), and as much of their captive husbandry is well known, they could an ideal system for studying the evolution of alternative reproductive strategies.

Factors influencing deceptive behaviours in Tonkean macaques (Macaca tonkeana)

The complex social environments of primates create opportunities for engaging in tactical deception, especially for subordinate individuals. We analysed the behaviour of subordinate Tonkean macaques with dominant conspecifics in an experimental food competition context. The subordinate macaque could see two pieces of food in a test area, but only one piece was visible to the dominant. Both individuals were released into the test area at the same time or with the subordinate given a short head start on the dominant. Here, based on video analysis of the subordinates’ behaviours, we describe and classify functionally deceptive behaviours displayed by subordinates, and report factors that influenced these behaviours. Subordinates used several types of tactical deception, including concealment and distraction, especially when paired with competitors of much higher social rank, and they obtained the hidden food more frequently when they used a combination of tactics rather than only one.