Deep Woodchip Litter: Hygiene, Feeding, and Behavioral Enhancement in Eight Primate Species

Sixty-seven animals from eight primate species were used to assess improved husbandry techniques. The presence of woodchips as a direct-contact litter decreased inactivity and fighting and increased time spent on the ground. Placing food in the deep litter led to further behavioral improvement. Frozen foods improved distribution and reduced fighting in most situations, especially when buried in the litter. With time, the litter became increasingly inhibitory to bacteria. The results suggest that inexpensive ways of increasing environmental complexity are effective in improving housing for primates

Individual differences in zoo-housed squirrel monkeys’ (<i>Saimiri sciureus</i>) reactions to visitors, research participation, and personality ratings

Understanding individual differences in captive squirrel monkeys is a topic of importance both for improving welfare by catering to individual needs, and for better understanding the results and implications of behavioral research. In this study, 23 squirrel monkeys (Saimiri sciureus), housed in an environment that is both a zoo enclosure and research facility, were assessed for (i) the time they spent by an observation window under three visitor conditions: no visitors, small groups, and large groups, and (ii) their likelihood of participating in voluntary research, and (iii) zookeepers ratings of personality. A Friedman’s ANOVA and Wilcoxon post-hoc tests comparing mean times found that the monkeys spent more time by the window when there were large groups present than when there were small groups or no visitors. Thus, visitors do not seem to have a negative effect and may be enriching for certain individuals. Through GLMM and correlational analyses, it was found that high scores on the personality trait of playfulness and low scores on cautiousness, depression, and solitude were significant predictors of increased window approach behavior when visitors were present. The GLMM and correlational analyses assessing the links between personality traits and research participation found that low scores of cautiousness and high scores of playfulness, gentleness, affection, and friendliness, were significant predictors. The implications of these results are discussed in relation to selection bias and its potential confounding effect on cognitive studies with voluntary participation

The visitor effect in petting zoo-housed animals: Aversive or enriching?

Two studies were carried out on the effect of visitors on mixed-breed goats, llama, and Vietnamese pot-bellied pigs housed in a petting zoo display within a safari park. In the first study we investigated the effect of the presence and density of visitors on the animals' behaviour and in the second, the effect of animal grooming by the visitors. We hypothesised that the animals' behaviour would be negatively affected by presence of visitors compared to periods of their absence, but this hypothesis was not fully supported by the data. Goat and llama behaviour was unaffected by the presence of the public, while the pigs showed decreased inactivity and social behaviour, both affiliative and aggressive, when visitors were present. All three study species exhibited increased levels of non-aggressive interaction with the public when visitor density was higher but the level of avoidance or aggression towards visitors was not dependent on density. The goats were less often in physical contact with other goats and less likely to be within proximity of a non-conspecific when visitor numbers were high, whereas the pigs showed decreased feeding, a behaviour that constituted a majority of their activity budget. Species differences were observed in the proportion of samples the study groups interacted in a non-aggressive manner with visitors, goats being most likely and llama the least likely to engage in this behaviour. In the second study visitors were provided with a grooming tool and asked to groom the animals, but no significant behavioural change was observed in either goats or pigs as a result. Visitors groomed goats, but not pigs, more than they interacted with them in non-grooming interactions, and goats, but not pigs, responded less to grooming as visitor density increased. Although significant behavioural changes in all three study species were associated with either visitor presence or density, the low levels of avoidance of visitors, visitor-directed aggression, or animal-directed aggression, suggest the welfare of the study animals was not profoundly impacted by visitor-related stimuli. Furthermore, there was no evidence that grooming by the public was enriching for the animals. The species differences reported here do suggest, however, that Vietnamese pot-bellied pigs and llama are more sensitive to visitor pressure than goats and particular attention to their welfare may be necessary when they are housed in petting zoo displays

Administration of thimerosal-containing vaccines to infant rhesus macaques does not result in autism-like behavior or neuropathology

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder. Some anecdotal reports suggest that ASD is related to exposure to ethyl mercury, in the form of the vaccine preservative, thimerosal, and/or receiving the measles, mumps, rubella (MMR) vaccine. Using infant rhesus macaques receiving thimerosal-containing vaccines (TCVs) following the recommended pediatric vaccine schedules from the 1990s and 2008, we examined behavior, and neuropathology in three brain regions found to exhibit neuropathology in postmortem ASD brains. No neuronal cellular or protein changes in the cerebellum, hippocampus, or amygdala were observed in animals following the 1990s or 2008 vaccine schedules. Analysis of social behavior in juvenile animals indicated that there were no significant differences in negative behaviors between animals in the control and experimental groups. These data indicate that administration of TCVs and/or the MMR vaccine to rhesus macaques does not result in neuropathological abnormalities, or aberrant behaviors, like those observed in ASD

Effects of visitor numbers on captive European red squirrels (Sciurus vulgaris ) and impacts on visitor experience

Visitors to zoological collections can have substantial effects on captive animals that vary according to species, enclosure design, visitor proximity, and husbandry methods. One particularly intense form of visitor interaction occurs in immersive exhibits such as walk-through enclosures. Such enclosures are increasingly common but effects on animal behavior are currently understudied. Here, the behavior of captive European red squirrels (Sciurus vulgaris) is studied in relation to visitor numbers in a walk-through enclosure. We also quantify the correlation between squirrel encounters and visitor experience. Interaction with humans increased significantly as the number of visitors inside the enclosure increased. The number of children present significantly increased locomotion and decreased eating, possibly due to disturbance and squirrels moving away from busy areas. By contrast, the number of adults significantly increased eating and decreased inactivity due to squirrels approaching visitors. The positive reinforcement training used by the keepers (offering food rewards to the squirrels for coming to them to allow routine medical checks) meant that squirrels associated adults with food opportunities. Squirrel encounter rate (number of squirrels seen by each group of visitors) was significantly affected by the number of adults and visitor duration (positive relationships) and noise as perceived by visitors (negative relationship). Encounter rate was positively correlated with overall visitor experience. Our results indicate that visitors affect behavior but this effect is influenced by husbandry methods. It is vital that visitors, especially children, minimize noise, and move slowly in the enclosure, both for the sake of the animals and their own experience

Is Wounding Aggression in Zoo-housed Chimpanzees and Ring-tailed Lemurs related to Zoo Visitor Numbers?

Chimpanzees in laboratory colonies experience more wounds on week days than on weekends, which has been attributed to the increased number of people present during the week; thus the presence of more people was interpreted as stressful. If this were also true for primates in zoos, where high human presence is a regular feature, this would clearly be of concern. Here we examine wounding rates in two primate species (chimpanzees Pan troglodytes and ring-tailed lemurs Lemur catta) at three different zoos, to determine whether they correlate with mean number of visitors to the zoo. Wounding data were obtained from zoo electronic record keeping system (ZIMS™). The pattern of wounds did not correlate with mean gate numbers for those days for either species in any group. We conclude that there is no evidence that high visitor numbers result in increased woundings in these two species when housed in zoos

Enriched Environment Experience Overcomes Learning Deficits and Depressive-Like Behavior Induced by Juvenile Stress

Mood disorders affect the lives and functioning of millions each year. Epidemiological studies indicate that childhood trauma is predominantly associated with higher rates of both mood and anxiety disorders. Exposure of rats to stress during juvenility (JS) (27–29 days of age) has comparable effects and was suggested as a model of induced predisposition for these disorders. The importance of the environment in the regulation of brain, behavior and physiology has long been recognized in biological, social and medical sciences. Here, we studied the effects of JS on emotional and cognitive aspects of depressive-like behavior in adulthood, on Hypothalamic-Pituitary-Adrenal (HPA) axis reactivity and on the expression of cell adhesion molecule L1 (L1-CAM). Furthermore, we combined it with the examination of potential reversibility by enriched environment (EE) of JS – induced disturbances of emotional and cognitive aspects of behavior in adulthood. Three groups were tested: Juvenile Stress –subjected to Juvenile stress; Enriched Environment – subjected to Juvenile stress and then, from day 30 on to EE; and Naïves. In adulthood, coping and stress responses were examined using the elevated plus-maze, open field, novel setting exploration and two way shuttle avoidance learning. We found that, JS rats showed anxiety- and depressive-like behaviors in adulthood, altered HPA axis activity and altered L1-CAM expression. Increased expression of L1-CAM was evident among JS rats in the basolateral amygdala (BLA) and Thalamus (TL). Furthermore, we found that EE could reverse most of the effects of Juvenile stress, both at the behavioral, endocrine and at the biochemical levels. The interaction between JS and EE resulted in an increased expression of L1-CAM in dorsal cornu ammonis (CA) area 1 (dCA1)