Social environment elicits lateralized behaviors in Gorillas (Gorilla gorilla gorilla) and Chimpanzees (Pan troglodytes)

The influence of the social environment on lateralized behaviors has now been investigated across a wide variety of animal species. New evidence suggests that the social environment can modulate behavior. Currently, there is a paucity of data relating to how primates navigate their environmental space, and investigations that consider the naturalistic context of the individual are few and fragmented. Moreover, there are competing theories about whether only the right or rather both cerebral hemispheres are involved in the processing of social stimuli, especially in emotion processing. Here we provide the first report of lateralized social behaviors elicited by great apes. We employed a continuous focal animal sampling method to record the spontaneous interactions of a captive zoo-living colony of chimpanzees (Pan troglodytes) and a biological family group of peer-reared western lowland gorillas (Gorilla gorilla gorilla). We specifically focused on which side of the body (i.e., front, rear, left, right) the focal individual preferred to keep conspecifics. Utilizing a newly developed quantitative corpus-coding scheme, analysis revealed both chimpanzees and gorillas demonstrated a significant group-level prefer- ence for focal individuals to keep conspecifics positioned to the front of them compared with behind them. More interestingly, both groups also manifested a population-level bias to keep conspecifics on their left side compared with their right side. Our findings suggest a social processing dominance of the right hemisphere for context-specific social environments. Results are discussed in light of the evolu- tionary adaptive value of social stimulus as a triggering factor for the manifestation of group-level lateralized behaviors

Does positive reinforcement training affect the behaviour and welfare of zoo animals? The case of the ring-tailed lemur (Lemur catta)

Positive reinforcement training (PRT) is an established tool to facilitate animal husbandry, care and research in modern zoos, with potential positive implications for captive animal welfare. The study explored the role of an isolation PRT training programme on the well-being of ring-tailed lemurs (Lemur catta). Eleven subjects were observed during an isolation training protocol to induce the animals to enter an area (training area) calmly and retrieve rewards separated from group members. Duration of individual and social behaviours were collected over two different periods: the baseline period, before the beginning of the isolation training protocol and the training period, in which the collection of the data started at the end of the isolation training sessions. Additionally, behavioural data within the isolation training sessions (latency to enter the training area and retrieve the reward, display of stress-related behaviours) were recorded. Outside the training sessions, lemurs were out of sight significantly more in the baseline (Mean ± SD: 15.46 ± 5.20) than in the training (Mean ± SD: 4.36 ± 2.89) period. Social behaviour was performed significantly more in the training (Mean ± SD: 31.80 ± 12.34) than in the baseline (Mean ± SD: 12.52 ± 5.14) period; particularly, lemurs were in social contact significantly more in the training (Mean ± SD: 14.09 ± 6.00) than in the baseline period (Mean ± SD: 4.58 ± 2.73). Agonistic behaviours were performed significantly more in the baseline (Mean ± SD: 0.23 ± 0.15) than in the training (Mean ± SD: 0.07 ± 0.07) period. Within the training sessions, all the individuals entered the training area, were isolated from conspecifics, and retrieved the reward in 6 out of 9 sessions. Our findings show that, during the PRT period, lemurs displayed their natural behaviour in their everyday social life with significant increase of their affiliative behaviours and decrease of aggressive behaviours with benefits for their welfare status. Thus, lemurs were able to cope with the use of PRT to isolate each individual from its social group – a situation which, without training, might be very stressful. In conclusion, PRT may play a crucial role for the captive management of ring-tailed lemurs in captive facilities, including zoos

A therapeutic environmental enrichment programme for managing pathological behaviour in the fossa (Cryptoprocta ferox)

This study is based on an adult male fossa (Cryptoprocta ferox) that arrived at Garda Zoological Park (Italy) exhibiting stereotyped and self-injuring behaviours and follows its subsequent rehabilitation through a long-term environmental enrichment programme. Data were collected over a period of six months. Continuous focal animal sampling was used to collect behavioural data during 90-minute sessions; 24 sessions took place over the first two months and two sessions took place six months after his arrival. Data were analysed using non-parametric tests. At the beginning of the study period, the predatory behaviour of the fossa was not species-specific since he was not able to find food items when they were hidden in the enclosure. It usually interacted with items for just a few minutes. Rub-bing different scents on enclosure furniture promoted play only for a few minutes. After two months of behavioural observations, its behaviour only improved slightly and stereotyped and self-injuring behaviours were maintained. However, we continued the intense enrichment programme for a longer period. Six months after its arrival rare undesirable behaviours or noticeable side effects were ob-served whilst species-specific behaviours were recorded. Results showed that the environmental enrichment curtailed the aberrant behaviours. In conclusion, this case study provides evidence sup-porting the hypothesis that a suitable enrichment programme could have a therapeutic effect on pathological behaviour in captive animals

Investigating parental care behaviour in same-sex pairing of zoo greater flamingo ( Phoenicopterus roseus )

This is the final version of the article. Available from PeerJ via the DOI in this record.Same-sex pair bonds have been documented in several animal species and they are widespread in birds. However, little is known about the evolutionary origin and the adaptive value of such behaviour. The aim of this study was to investigate the parental behaviour of four zoo female greater flamingos involved in two breeding pairs, housed in a flock at Parco Natura Viva, Italy. Further, the behaviour of the study females was compared with that of male and female flamingos in heterosexual pairs described in a previous published work on this same flock. For each pair, the behaviour of both birds during the incubation period was recorded and twenty 10-minute sessions were run within the incubation period. A continuous focal animal sampling method was used to collect data on location (on the nest or not on the nest) and the parental care behaviour (e.g.: agonistic behaviours toward disturbing conspecifics, egg-care, nest-building, self-comfort behaviour, sleeping) of the two pairs. Data of the current study females were compared with those of females and males involved in heterosexual pairs of this same flock. Results showed that within each pair the egg-layer female stayed away from the nest more than the other female. In addition, the female that did not lay an egg was more involved in agonistic behaviour compared to other females, particularly when in specific locations. In heterosexual pairs, male flamingos were more involved in the incubation and in nest protection. Moreover, no significant differences in the time spent on the nest and away from the nest between the heterosexual male and the non-layer females of same-sex pairs were found. The same findings were reported when comparing heterosexual females and the egg-layer females of the same-sex pairs. Therefore, our findings suggest that in greater flamingos the behaviour of the female–female pairs seems to be equivalent to that of male-female bonds. Such research provides more insight into flamingo social behaviour, and their reproductive cycle, and provides information on why pair bonds may form and how these affect the wider breeding behaviour of the flock

Red-green color vision in three catarrhine primates

The evolution of the red-green visual subsystem in trichromatic primates has been linked to foraging advantages, specifically the detection of either ripe fruits or young leaves amid mature foliage, and to the intraspecific socio-sexual communication, namely the signal of the male rank, the mate choice and the reproductive strategies in females. New data should be added to the debate regarding the evolution of trichromatic color vision. Three catarrhine primates were observed to achieve this goal. The research was performed on captive groups of vervet monkeys (Chlorocebus aethiops), pig-tailed macaques (Macaca nemestrina) and chimpanzees (Pan troglodytes) housed at Parco Natura Viva - Garda Zoological Park (Italy). Using pairs of red-green bags containing the same hidden reward in comparable outdoor enclosures, we recorded the choices by observed individuals (n = 25) to investigate the role of color cues in choosing an object. The results indicate that chimpanzees used red color as cue to choose an object that contains food by showing a preference toward red objects; in contrast, vervet monkeys and pig-tailed macaques do not demonstrate a clear choice based on the color of the object. Our findings highlight the importance of the foraging hypothesis but not rule out the potential role of the intraspecific socio-sexual communication and may serve to add useful information to the debate regarding the adaptive value of the evolution of color vision in order to fill a phylogenetic gap from Old World monkeys to humans. Future studies should address the role of socio-sexual communication, such as the selection of the reproductive partner of both high genetic quality and with compatible genes, to determine how this influenced the evolution of color vision in non-human primates

Gum-feeder as environmental enrichment for marmosets and tamarins

Tamarins and marmosets are small‐bodied social callitrichines. Wild callitrichines feed on exudates, such as sap and gum; particularly, marmosets are mainly gummivores, while tamarins consume gums only occasionally and opportunistically. Zoo marmosets and tamarins are usually provided with gum arabic as an alternative to the exudates normally found in the wild. The aim of this study was to evaluate the effects of a gum feeder on the behavior and well‐being of four zoo‐managed callitrichines. We studied four cotton‐top tamarins (Saguinus oedipus), four red‐handed tamarins (S. midas), two pygmy marmosets (Cebuella pygmaea), and three Geoffroy's marmosets (Callithrix geoffroyi) housed at Parco Natura Viva (Italy). We conducted the study over two different periods, a baseline (control, without the gum feeder) and then a gum feeder (when the gum feeder was provided) period. We used continuous focal animal sampling to collect behavioral data, including durations of social and individual behaviors. We collected 240 min of observations per period per study subject, with a total of 3,120 min for all the subjects in the same period and of 6,240 min in both periods. We analyzed data by using nonparametric statistical tests. First, we found that the gum feeder promoted species‐specific behaviors, such as exploration, and diminished self‐directed behaviors, suggesting an enriching effect on tamarin and marmoset behavior. Moreover, in red‐handed tamarins, the provision of the gum feeder reduced the performance of self‐directed and abnormal behavior, specifically coprophagy. These results confirm that gum feeders are effective foraging enrichment tools for zoo marmosets and tamarins

Personality assessment and effect of visitors on a group of lions (panthera Leo) hosted in captivity

In the last 10 years researches have been focused on the impact of personality on welfare, health and management of zoo animals. The present study, as part of a wider research in European Zoos, had the purpose to identify the personality of three female and one male lions housed at Parco Natura Viva - Garda Zoological Park. Moreover, since researches have reported significant effects of visitor presence on zoo animals, in particular primates and felids, the effects of visitors on the behaviour of these animals was also evaluated. The study was made of two different periods, one in the presence and one in the absence of visitors. Data on individual and social behaviours were collected using focal animal sampling method. The enclosure was ideally divided in different zones. During each observational session, the zone in which the animal was, the position of body, the proximity to conspecifics were also collected. The time budget, the association index and the sociogram were then calculated. Besides, a survey (modified from Chadwick, 2014) was proposed to the two keepers of the lions. The questionnaires listed 31 traits rated on a scale from 1 (trait was never exhibited) to 12 (trait was always exhibited) by the keepers for each lion. Personality profiles were defined for each individual through the questionnaires correlated with behavioural data. Statistical analysis within subjects underlined a significant difference in the following traits: curious, friendly to conspecifics, playful, solitary. In addition, the ANOVA (F-test) assessed a significant difference between the two periods of observation (with and without visitors) for the curious, eccentric, playful and vocal traits. The results showed that the different personality between animals seems not be related to age, gender or rearing history. Studies about animal personality are useful to guarantee a good care and the management of each individuals