Abstract: We review studies demonstrating the ability of some animals to understand the human pointing gesture. We present a 3-step analysis of the topic. (1) We compare and evaluate current experimental methods (2) We compare available experimental results on performance of different species and investigate the interaction of species differences and other independent variables (3) We evaluate how our present understanding of pointing comprehension answers questions about function, evolution and mechanisms. Recently, a number of different hypotheses have been put forward to account for the presence of this ability in some species and for the lack of such comprehension in others. In our view, there is no convincing evidence for the assumption that the competitive lifestyles of apes would inhibit the utilization of this human gesture. Similarly, domestication as a special evolutionary factor in the case of some species falls short in explaining high levels of pointing comprehension in some non-domestic species. We also disagree with the simplistic view of describing the phenomenon as a simple form of conditioning. We suggest that a more systematic comparative research is needed to understand the emerging communicative representational abilities in animals that provide the background for comprehending the human pointing gesture.

Abstract: The global positioning system (GPS) has been used to record activity and monitor habitat use in many animal species. In the horse (Equus caballus) the monitoring of activity and feeding patterns has been used to assess the impact of environmental factors on behaviour and welfare. In free-ranging animals GPS can provide such information but the accuracy and reliability of these devices has yet to be confirmed. The aim of this study was: 1) to compare the results of visual observation with GPS recordings of the horse’s head and neck position (head up (HU) and down (HD)) used to quantify time spent grazing; 2) to test the use of GPS collars to monitor activity patterns where distance, speed and location paths were recorded. In both studies two animals were fitted with Lotek GPS 3300S collars (with integrated GPS data logger and removable battery pack) round the top of the neck. In study 1 two horses were fitted with collars and turned loose into a 20x40m sand arena for 45 minutes. Feed balls and hay were provided (in nets and on the ground) to encourage movement and feeding behaviour for comparison using the two methods (observation from digital video recordings and GPS). HD was recorded by the GPS collars for a significantly longer time (interpreted as feeding/grazing time) than that recorded by observation (p=0.004). However when the visual observation was split into HU, HD and also head in mid-way position (HMW), where the nose of the horse was level or just above the chest, then no difference between the collar (HU and HD) and visual observation for (HU and HD+HMW) was found. It is likely that when in HMW the GPS collar may not be sufficiently angled to trigger the sensor to record HU or the collar may move on the neck. Conclusions relating to time spent feeding should be treated with caution. In study 2, the collars were fitted to two ponies with access to 2.02 hectares of lowland grazing. Activity (distance travelled and speed) and location was recorded for 2 days. The total distance travelled by the ponies in 24 hours (2.84km) and their average speed (4.04m/minute) was calculated and showed no significant difference between day and night. The total area was split into four equal segments and there was no significant difference in the time the ponies spent in each area although they were found to move at slower speeds and stand for longer in some areas. Movement paths could be identified by inputting the GPS collar data into ArcGIS and viewed on Google Maps. There was a high level of comparability observed between the two ponies confirming behavioural synchronicity. As in other species, the use of GPS collars to monitor the movement and location of horses/ponies was found to be effective, but data relating to head position did not provide a reliable means of recording the time spent feeding.

Abstract: Gestures and facial displays are involved in regulating many aspects of mammal social life such as aggression, dominance-subordinate relationships, appeasement and play. Playful activity is an interesting behaviour for examining the role of signals as intentional communication systems. When animals play they perform patterns that are used in other serious contexts. To avoid miscommunication, many species have evolved signals to maintain a playful mood. Bonobos, Pan paniscus, with their flexible social relationships and playful propensity, may represent a good model species to test some hypotheses on adult play signalling. I analysed the potential roles of facial play expressions and solitary play in soliciting and regulating social play and found that adult bonobos used the play face (relaxed open-mouth display) in a selective manner. Play faces were more frequent during social than solitary play and, within social play, polyadic sessions (even though less frequent than dyadic sessions) were characterized by a higher frequency of signals. Following the rule of play intensity matching, play faces were more frequent when the two players matched in age and size (sessions among adults). Moreover, among dyads there was a positive correlation between the frequency of aggressive interactions performed and the frequency of play signals used, thus suggesting that signals are crucial in play negotiations among individuals showing high baseline levels of aggression. Finally, solitary play, especially when it involved pirouettes and somersaults, had an important role in triggering social play.

Abstract: The ability of organisms to discriminate social signals, such as affective displays, using different sensory modalities is important for social communication. However, a major problem for understanding the evolution and integration of multimodal signals is determining how humans and animals attend to different sensory modalities, and these different modalities contribute to the perception and categorization of social signals. Using a matching-to-sample procedure, chimpanzees discriminated videos of conspecifics' facial expressions that contained only auditory or only visual cues by selecting one of two facial expression photographs that matched the expression category represented by the sample. Other videos were edited to contain incongruent sensory cues, i.e., visual features of one expression but auditory features of another. In these cases, subjects were free to select the expression that matched either the auditory or visual modality, whichever was more salient for that expression type. Results showed that chimpanzees were able to discriminate facial expressions using only auditory or visual cues, and when these modalities were mixed. However, in these latter trials, depending on the expression category, clear preferences for either the visual or auditory modality emerged. Pant-hoots and play faces were discriminated preferentially using the auditory modality, while screams were discriminated preferentially using the visual modality. Therefore, depending on the type of expressive display, the auditory and visual modalities were differentially salient in ways that appear consistent with the ethological importance of that display's social function.