1. Other independant variable
Carretera de Cassà, 1km · 17457
Riudellots de la Selva · Girona (Spain)
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Does more mean better? Impact of two simultaneous different types of enrichment in chimpanzees (Pan troglodytes)
Noëlla Iglesias1,2, Miquel Llorente2,3
1 · Fundació Universitat de Girona: Innovació i Formació, Girona, Spain 2 · Unitat de Recerca i Etologia, Fundació Mona, Riudellots de la Selva – Girona, Spain 3 · IPHES, Institut Català de Paleoecologia Humana i Evolució Social, Tarragona, Spain
Correo electrónico:
Keywords
Carretera de Cassà, 1km · 17457
Riudellots de la Selva · Girona (Spain)
Telf.: (00 34)
Chimpanzee; cognitive enrichment; sensorial enrichment; well-being
1. INTRODUCTION
2. MATERIALS & METHODS
Captive great apes live in very poor environments compared to their natural habitat. This very restricted and predictable environment can affect the behaviour of these individuals, and therefore their well-being (Clark, 2011).
One possibility to increase the well-being of captive animals, is the use of enrichments. With the use of cognitive challenges a new category has appeared: the cognitive enrichment.
2.1. SUBJECTS & HOUSING
Thirteen chimpanzees (Pan troglodytes), nine males and four females, aged from 11 to 32 years, were studied in the Fundació Mona Primate Rescue Center (Girona, Spain).
Subjects lived separated into two groups: (Group A) five males, and (Group B) four males and four females.
2.2. PROCEDURE
In chimpanzees (Pan troglodytes) Clark and Smith (2013) showed that when cognitive enrichment was available for the chimpanzees, it increased social play. And, as they said, play is a “pleasure” behaviour which may indicate a positive affective (emotional) state.
Regarding chimpanzees, it has also been proved that music has a positive effect on well-being (Howell et al, 2003), and so can be used as enrichment. Furthermore, different types of music appear to have different effects (Videan et al., 2007).
But what happens when you add several types of enrichment at the same time?
Two different types of enrichment were used: a cognitive and a sensorial enrichment.
Cognitive enrichment: tubes with double exit, with food inside were used (length = 1 meter, diameter = 13 cm, with holes of 1.5 cm of diameter all over the tubes).
2.3. DATA
Chimpanzees should use instrument like woodsticks to get the reward (roasted corn). We put two tubes for each group (red star at Figure 1). No individual was familiar with this enrichment.
Sensorial enrichment: instrumental music stimuli, two speakers were put inside the perimeter of the main outdoor enclosure, specifically at the intersection of the two subareas (music note at Figure 1).
Data analysis was structured in two parts: activity budget (Rates of behaviours per minute); and welfare indexes.
Welfare indexes: behavioral competence index (BCI) and social competence index (SCI). Values of SCI and BCI index range between -1 and +1 (Llorente et al., 2015).
All the data was analyzed using a Generalized Linear Mixed Model.
We studied the effect of a sensorial enrichment (instrumental music) and a cognitive enrichment, used separately (only sensorial enrichment, or only cognitive enrichment) and simultaneously (sensorial and cognitive enrichment at the same time), on activity budget and welfare indexes.
Music (1)
Base Line  Music + Cognitive challenge (3)  Base Line Post-test Cognitive challenge (2)
(BL)
(POST)
Treatment (TR)
Phase of the study
3. RESULTS
2.2. GENERAL EFFECT OF THE STUDY
2.1. DIFFERENCES BETWEEN CONDITION (1)/(2)/(3)
Positive effects
Other independant variable
Residual effect
Negative effects
↓ Abnormal behaviours
Individuals, presence of new individuals No
↓ Alimentation
Yes
↑ Locomotion
Individuals
↑ Inactivity
Individuals, moment of the day
↑ Manipulation
↓ Grooming
Moment of the day, temperature, individuals
↑ Affiliative behaviours
↓ SCI
Group, presence of new individuals
Graphic1: Alimentation in the budget activity
Graphic 2: Grooming in the budget activity
Table 1: Positive and negative effects of the study
Significative differences in 3 behaviours: alimentation, grooming and agonistic behaviours
But, other independent variables were found with significant effect too:
Effect of individuals and group on alimentation
Effect of individuals on grooming
Tendencies (p near 0.05)
-↑ Affiliative behaviours in condition 1 and 3
-↑Manipulation in condition 2 and 3
Graphic 3: Agonistic behaviours in the budget activity
5. CONCLUSION
4. DISCUSSION
For feeding, agonistic behaviours, and also majority of index and behaviours where tendencies were founded, we can see that rate of condition (3) is nearest that the rate of condition (2). Without forget that others independent variables have significant effects too, can it be possible that, in this study conditions, cognitive enrichment had a stronger effect than sensorial enrichment?
Results expected and obtained
Increase of manipulation thanks to the cognitive challenge
Increase of affiliative behaviours thanks to the sensorial enrichment (Videan et al., 2007)
Others independent variables with significant effect:
Presence of 3 new individuals in group (B) = increase of social behaviours, decrease of individual behaviours (ex: abnormal behaviours)
Group effect: one group with males only, one group with males and females, (ex: group with only males do significantly more locomotion). Furthermore, it seems like there were changes in the dominance order in group (A), which can be an explanation for the evolution of social competence index during this study,
Individual effect
In these conditions, with these independent variables and these individuals, adding two enrichments at the same time had positive effects, more than with the use of only one. Negative effects seem to add up too, but they are not all residual. So, before using two enrichments simultaneously, the objective has to be clearly defined, with the pros and the cons, in order to see if it is worth it. Furthermore, to exclude effect of independent variables and know more about this enrichment option, further research is needed, with, for example, stable groups and/or more data.
References
Birkett LP, Newton-Fisher NE (2011) How Abnormal Is the Behaviour of Captive, Zoo-Living Chimpanzees? PLoS ONE 6(6): e20101.doi: /journal.pone
Clark FE, Great ape acognition and captive care: Can cognitive challenges enhance well-being? Applied Animal Behaviour Science 135:1-12
Clark FE & SMITH LJ, Effect of a Cognitive Challenge Device Containing Food and Non-Food Rewards on Chimpanzee Well-Being. American Journal of Primatology 9999:1-10
Howell S, Schwandt M, Fritz J, Roeder E, Nelson C A stereo music system as environmental enrichment for captive chimpanzees (Pan troglodytes). Lab Anim 32:31–36.
Videan EN & al, Effect of two types and two genre of music on social behavior in captive chimpanzees (Pan troglodytes). Journal of the American Association for Laboratory Animal Science 46(1):66-70
Acknowledgments
Thanks to Alba Gómara, Cristina Valsera and Crailsheim Dietmar, the three headkeeper of Fundacio Mona, for their collaboration, comments and help all along the study. Thanks also to David Riba for his availability, patience, support and his thoughtful advices. And thanks to Daniela D’amore and Rocío Angulo, for her hudge support and comments all along the process of writing the manuscript and making this poster.