MANAGING A DESTRUCTIVE ORANGUTAN

Transcription

1 MANAGING A DESTRUCTIVE ORANGUTAN Fleur Butcher, Zoos Victoria Melbourne Zoo has held Orangutans since 1882 and currently cares for two males and four females. In 2013 Malu, a 9-year-old male, started to develop what we referred to as destructive behaviour where he would spend a significant amount of time working to damage or pull apart items within the enclosure. The severity of this behaviour progressively increased over the following 1.5 years as his strength and skills developed. Although this behaviour is not unusual in Orangutans, it became of concern for several reasons. Firstly, zoo staff were concerned that it was a redirected behaviour as a result of frustration or under-stimulation in his environment, which was of obvious welfare concern. Secondly, it was also of concern because his actions started to compromise the structural integrity of the exhibit, which resulted in near escapes, injuries to himself, other orangutans and staff. Thus, a research program was developed in order to provide insight into interventions that could reduce this behaviour. We were interested in testing the effectiveness of three different interventions in reducing this behaviour, including: 1.Enrichment. 2. Social Vs solitary 3. Fixed territory We evaluated changes in activity budgets and faecal glucocorticoid metabolite concentration (FGM), as a measure of physiological stress, in all orangutans within the group. This paper presents the results of this research and discusses post research management of this individual, and potential implications for other individuals with similar behavioural problems. BACKGROUND Facilities and Routine The Melbourne Zoo Orangutan Sanctuary consists of three exhibits and 10 dens including an open exhibit with wooden poles and platforms, metal poles joined with rope, and ground cover vegetation. An enclosed exhibit made from stainless steel mesh, wooden platforms, hanging poles and fire hose, and an indoor Dayroom which is an indoor display space (see Fig 1). Santan and Malu have visual access during the day, but no physical contact. Pre-study we had a flexible routine. All individuals were moved through the three exhibits each day and had no fixed den overnight. All orangutans are trained and fed in dens in the AM. Each exhibit is set up with enrichment and bedding and all animals are on display by They are shifted in at least once during the day where they are fed inside while the exhibit is set up with enrichment. The daily routine is not locked in and if staff have 1

2 more time they may do an extra shift or training on display. Orangutans are brought in at 4pm to enrichment and diet. If weather is warm some individuals may have exhibit access over night. Figure 1. Diagram of the Melbourne Zoo Orangutan Sanctuary Malu rearing history and behaviour Malu was mother reared and introduced to Santan his father at 17 months and remained with continuous day time access to him until he was 7 years old. During these early years, Malu spent large amounts of time wrestling with Santan. However, due to increasing aggression between Malu and Santan, access gradually reduced until they were separated permanently when Malu was 10 years old. When Malu was 7 (2010) he was introduced to a mother/daughter pair Kiani and Gabby also living at the orang-utan sanctuary at Melbourne Zoo. Malu s destructive behaviour shows his amazing intelligence and tool use. He tends to identify a flaw in the exhibit which can act like a project for him, where he continues working at the structure until he succeeds in taking it a part. Some examples of this include; removing clamps from ropes, removing planks of wood from the deck, breaking nipple drinker pipes, removing metal window frames, breaking enrichment balls, removing metal poles and breaking arboreal feeders. The first record of his destructive behaviour (2 recorded bouts) was in 2012 and in 2013 his destructive behaviour increased dramatically (11 recorded bouts). Around the same time, he started showing bouts of lethargy. In 2013 he had 3 recorded bouts of this behaviour. There appeared to be a possible correlation between tooth eruption and lethargy. In 2014 we saw a dramatic escalation in both the destruct and lethargy behaviours. Numerous near misses occurred as a result of Malu destroying items within all three exhibits at the sanctuary. 2

3 RESEARCH PROJECT A research project was conducted 23/07/14 31/10/14 to further investigate Malu s destructive behaviour. The aims include: 1. To determine the effectiveness increased intensity of enrichment has in reducing Malu s destructive behaviour. 2. To evaluate how social interaction with Kiani and Gabby influences Malu s behaviour and stress physiology. 3. To determine the effect of reducing visual contact with Santan and maintaining a fixed territory influences Malu s behaviour and stress physiology. METHODOLOGY The research was conducted as three separate studies to allow the effectiveness of each intervention to be evaluated independently. A two-week baseline data collection period was conducted. Followed by an Enrichment study, then the Social study, Fixed territory study. Throughout the entire research period (baseline and all 3 experiments), Malu s behaviour was monitored using the same sampling techniques. This involved 24 hour behavioural sampling, using direct observations during the day and motion-sensor camera recordings overnight. Diurnal behavioural observations involve the researchers observing Malu in three blocks, continuously recording any bouts of destructive behaviour or other abnormal behavior. In addition, the average time spent engaged in other activities (foraging, locomotion, using enrichment, resting and social interaction) was recorded using instantaneous scan sampling at 3 min intervals in 3X 1 hour blocks throughout the day. Stress levels were assessed for the Orangutan group by collecting a faecal sample from the dens every morning throughout the study. 3

4 Enrichment study Two treatments were studied 1) intense enrichment and 2) standard enrichment. Treatments were imposed using a switchback design for 5 days at a time, with a 2 replicates of each treatment through the study (5 replicates in total, over 20 days). Malu s behaviour and stress levels were monitored on each study day according to protocol described above. Novel items that Malu has never been exposed to (e.g. substrate piles, large adventure balls, projectors, lights, new hammocks, playground equipment) were used in combination with increased frequency of provision of items. Enrichment items were provisioned every hour to hour and a half between 0930am and 4.00pm. An on display training session was conducted during intense treatments. Social housing study Following the enrichment study, Malu s social contact was manipulated and two treatments were studied 1) social contact with Gabby and Kiani and 2) solitary housing. The study was conducted for a total of 4 weeks with Malu spending 4 days in Social contact and 3 days alone each week. Fixed territory study For the fixed territory study visual contact between Malu and Santan was reduced using visual barriers and increased housing separation. Malu was given his own den space overnight. Two treatments were studied 1) reduced visual contact and fixed territory and 2) standard housing routine which involved rotating through every exhibit each day. RESULTS Enrichment study During the intense enrichment treatment, the frequency of the provisioning of enrichment per day increased from an average of 3.53 sessions per day during baseline to 5.56 sessions per day in the intense enrichment treatment. The intense enrichment treatment significantly reduced Malu s destructive behaviour from 63 events of this behaviour observed during normal enrichment treatment days versus 7 bouts of this behaviour observed during intense enrichment treatment days. Over time the effectiveness of reducing destruction during Intence enrichment reduced, but his enrichment usage increased. Furthermore, overnight activity observations showed an average of 5.2 bouts of activity during normal enrichment treatment, which reduced to 1.8 bouts of activity during the intense enrichment treatment. Results also demonstrated that Malu spends the most time engaging with enrichment provided out of all the Orangutans 4

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6 Social study Although not statistically significant, the number of destructive events performed by Malu was higher in the social treatment, with 61 bouts recorded when he had social contact and 21 events recorded when he was housed alone. Furthermore, keepers reported that on Malus alone days his lethargy increased and it became increasingly difficult to get him to go out on display (pers obs). Malu also rested more during alone time and engagement with enrichment use was greater during his alone time. 6

7 The average overnight activity during the social study was 4.57 bouts of activity and on alone days it was 6.0. Fixed territory When we moved from the fixed territory treatment back to normal rotation, Malus destruct behavior increased immediately. Events went from 0.3 per hour to 1.3 per hour. Aggressive behavior increased slightly during fixed territory for Gabby, Kiani, Mai, and Malu, however this was not statistically significant. During the fixed territory treatment, the average overnight activity was 7.4. The average was increased by one night when there was a function in the 7

8 Orangutan Sanctuary. On this night there were 22 bouts of activity. With this night removed the average was 6.1. Faecal glucocorticoid metabolite concentration (FGM) FGM concentrations are only useful looking at within-individual variations across the treatments and individual responses to events. This is because there is large variation in baseline FGM concentrations between individuals. 8

9 There was no significant effect of any of the treatments studied on individual FGM concentrations. However certain trends were observed. Of Malus top 10 average concentrations 5 of these days were alone days and 5 were rotational housing days. Results also showed some correlations in peak concentrations between individuals around clusters of dates. For example, 5 of Malu s peak concentration levels coincide with Kiani s peak levels. Mai s highest concentration occurred around the 15 th of September. The one event we can collate this was an overnight function above the Orangutan dens. Malu was also very active overnight with an activity peak of 22 bouts with his normal average 7.4. Mai, Gabby and Kiani all had concentrations which were in their top 5 peaks. Other unusual behaviour which occurred within a 24hour period were Santan regurgitating, Mai excessively pacing and Gabby producing loose faeces. DISCUSSION Environmental enrichment can be defined loosely as an animal husbandry principle that seeks to enhance the quality of captive care by identifying and providing environmental stimuli necessary for optimal psychological and physiological wellbeing [Shepherdson, 1998]. As part of Zoos Victoria s goal of becoming a world leading zoo-based conservation organization we are committed to providing excellence in animal care. Enrichment has been an important part of husbandry at Melbourne Zoos Orangutan Sanctuary. There is always differences in levels of provisioning and differences of opinions in the usefulness of an enrichment program. The increased frequency and intensity of provisioning during this study would be difficult to continue long-term with current resources. But the significant reduction in Malus destruct behavior shows that an increase in enrichment is a very useful tool which should be considered. For the Social part of the study we wanted to evaluate how social interaction with Kiani and Gabby influences Malu s behaviour and stress physiology. Housing Orangutans in a captive setting means we expose them to social situations not always the same as their wild counterparts. Orangutans are highly intelligent and adaptive. They have their own personality and individual preferences. There appears to be some great variations in sociality not only between species but also between populations with species. The Sumatrans species is more gregarious than the Bornean. There is also great variation in sociality depending upon sex and age. In Tunjung Putting sub adult male Orangutans begin travelling separately from their mother at approximately 9 years of age reaching subadulthood at years of age. In the study site sub adult males were observed with females 83.8%, males 3%, and male and female groups 13.7% (Galdikas 1985). Malu had an increase in lethargy during alone times. He was increasingly difficulty to shift and get out on display. He was observed doing some abnormal behaviours on these days such as copraphargy and hair plucking. During the study period Malu had some teeth come through which appeared to cause pain, he appeared depressed and remained in bed for the mornings. He responded well to Panadol. It is hard to say how much of this behaviour was pain or lack of social interaction. 9

10 A population studied in Sumatra showed that dominant male Orangutans in the area had a more limited range than other adult males and females. Female orangutans form stable home ranges which overlap with both males and females. Females range from 500 to 850 ha areas that overlap with each other. Males have a minimum range of 2,500 ha that will cover up to three female home ranges. (Singleton and van Schaik, 2002) In Borneo Galdikas' long-term observations indicate that the pattern of residency may not be permanent, since regularly observed males left her study area after resident females gave birth. Observations of interactions of adult males in Kutai National Park showed that between adult males, they were more tolerant of sub adult males, and sub adult males rarely showed any overt antagonism toward each other. Adult males were intolerant of each other. (Mitani 1985) Moving from fixed to rotation territories appeared to be a trigger for Malus destruction during the study. Further research into this treatment would be beneficial. Is his increase in destruction due to moving into Santans territory or is it due to moving into a new and novel space? During the fixed territory we had a visual barrier hanging in the visitor centre, blocking direct visual contact between the open and enclosed exhibits. Being a subadult male Malu should not be a threat to Santan. We often see Santan looking at all the other Orangutans through the windows, some days he seems to pay special attention to Malu. It is interesting to note that none of our Orangutans had significant (FGM) concentrations related to study treatments. Peaks in fluctuations appear to be result from events rather than the different treatment during the study period. It has often been hypothesized that the stress of being in close proximity to a dominant male is enough to suppress the development of secondary characteristics in other males. (Maggioncalda 2002) Found no evidence for the idea that arrested secondary sexual development is associated with basal activation of the stress-response; thus, arrested adolescence may occur as an adaptation to avoid chronic stress, rather than as a result of it. Arrested adolescents, i.e., males without secondary sexual features, avoid aggression, injury, and chronic stress, while still being able to produce offspring. The SSP Animal Care Manual states the following: Sub adult is the term applied to males with arrested secondary sexual maturation. Both in captivity and the wild, the maturation process can take as little as a few months or as long as 10 years (MacKinnon, 1979; te Boekhorst, 1990). According to Maple (1980), it has been unwritten zoo lore that the complete development of secondary sex characteristics seems to be suppressed in young male orangutans housed with adult males. However, if the dominant male is removed, the suppressed male begins to develop immediately. Importantly, it has been noted that the transformation from sub adulthood to full adulthood in male orangutans is sudden and dramatic, and in the wild it takes only a few months (MacKinnon, 1979). Morphological and behavioral differences between dominant and subordinate male orangutans have been observed both in captivity and in the wild. The arrest of secondary traits is not permanent, but is known to last up to seven years in captivity (Kingsley, 1988) and for ten years or more in the wild (te Boekhorst et al., 1990). Based on the endocrine data together with behavioral information, it appears that male orangutans have evolved a flexible developmental timeline, whereby subordinate males may postpone secondary sexual development in order to avoid aggression and stress, but retain timely primary sexual maturation and achieve reproductive success. 10

11 HUSBANDRY CHANGES In response to preliminary results and an increase in destructive behaviour the following husbandry changes were implemented. 13/01/15 onwards Fixed territories implemented. 21/01/15-05/06/15 Follow up observations by Research volunteer Maddi Chambers 20/02/15-15/07/15 Malu Focal Days The research volunteer recorded Malu s destruct behaviour on Mondays, Wednesdays and Fridays. Destruct frequency pre focal days was 10. Post focal days reduced to 3, with an elevation when focal days are less intense due to staff commitments (Wednesday), and with increasing frequency in afternoons. July 2015 Malu escaped from the mesh exhibit using a blanket to snap the mesh. He no longer has access to the mesh exhibit. Enrichment Over the past 3 years the enrichment program has dramatically reduced to accommodate Malu s destructive behaviours, staffing levels and the ceasing of the volunteer program. The dynamic nature of the exhibits has been reduced as a result of his destruction. Previously enrichment was at the discretion of individual keepers. We now have a minimum daily requirement, which is 3 items per day and a calendar which is signed off each day. Training Overview Malu engages really well for training sessions. His painting has really developed over the past 12 months. He enjoys using an I-pad. One of Malus undesired behaviours which developed over the past couple of years is the capture, torture and killing of possums. We worked hard on a possum leave behaviour and are now mostly able to retrieve possums unhurt. When Malu escaped from the exhibit staff were able to call him over and give him a hand injection. We have also worked hard not reinforcing him when he breaks items. A fun behaviour we have worked on has been construct. Over time we have progressed to giving him lego blocks. This is a hit with both him and our visitors. RECOMMENDATIONS FROM 2015 ORANGUTAN HUSBANDRY WORKSHOP The 2015 Orangutan Husbandry workshop used Malus case in one of the problem solving sessions. The following recommendations were presented to Melbourne Zoo management Increase enrichment. Has not been achieved. During a peak 12-month period of Malus destruction our volunteer s enrichment program was disbanded pending review. This has now been reinstated. Malu is restricted to our Open exhibit which has been stripped of enrichment and furniture due to his destruction. This space is very challenging to enrich now. No loose items, no blankets, no attached items.

12 2. Reduce staff turnover. This is being addressed as we speak. 3. Exhibit modifications. Many modifications have been carried out to prevent escape and damage 4. Transfer. Unfortunately, this has just been taken off the table. We are now looking for long-term housing solutions for Malu in Melbourne. RECOMMENDATIONS 1.Create Malu safe exhibits Start planning long term on site housing for Malu. Start design of new exhibit and dens. Carry out renovations of current exhibits to make them safe to house him. This would include replacing the mesh on the enclosed exhibit to a thicker guage. Removing and replacing all the furniture in the Open exhibit. Create a mesh roof over the Open exhibit. 2. Visual Barriers The study showed that fixed territories are beneficial. During the study period a visual barrier was hung to reduce direct visual contact between Malu and Santan. He spends large amounts of time looking at Malu through the lower Dayroom windows they should be painted. A simple study could be carried out by WCS volunteers to look at the benefit of the visual barrier. 3. Enrichment Implement new enrichment items, including the Microsoft connect and Willy Wonka Enrichment Zone. Increase enrichment items to a minimum of 4. Implement one intense enrichment day per week. Invest immediately into getting some enrichment installed into the open. Increase height of a small area of the public barrier so loose enrichment items can be used in exhibit without risk to visitors. Carry out study to look at ideal activity levels and Orangutan time budgets to create a more focused enrichment program. 4. Husbandry changes to include choice Change husbandry practices to increase opportunities for choice and control 5. Monitoring cortisol FGM concentrations showed peaks in multiple individuals following a overnight function. A follow up study should be conducted by WCS 12

13 6. Improve remote monitoring from dens and office with camera installations This will give keepers more opportunities to intervene before Malu breaks items. Currently when keepers physically check on him his behavior alters. 7. Reinstate Malu focal days with clear criteria Ceased in July A very valuable tool. Implement 1 Malu focal day per week. ACKNOWLEDGEMENTS Sally Sherwen, Michael Magrath, Maddi Chambers, Harna Burton, Melbourne Zoo Primate team, Melbourne Zoos Orangutans Santan, Maimunah, Malu, Dewi, Kiani and Gabby. REFERENCES Galdikas B.M.F Subadult Male Orangutan Sociality and Reproductive Behavior at Tanjung Putting. American Journal of Primatology (1985) Maggioncalda. A. Male Orangutan Subadulthood: A New Twist on the Relationship between Chronic Stress and Developmental Arrest. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 118:25 32 (2002) Valerie J. Hare1 and Marty Sevenich2. IS IT TRAINING OR IS IT ENRICHMENT? The Shape of Enrichment, Inc. Desmond T. BEHAVIORAL MANAGEMENT AN INTEGRATED APPROACH TO ANIMAL CARE President Active Environments Valdovinos E. Effect of Enrichment Items on the Aggression and Competition Levels of Captive Orangutans Goshert C. Animal Enrichment for Captive Orangutans at Racine Zoological Gardens Schilbach C. Marcílio N Effect of Environmental Enrichment on Behavioral and Endocrine Aspects of a Captive Orangutan (Pongo pygmaeus) Singleton I. Van Schaik C the Social Organisation of a Population of Sumatran Orang-Utans Mitani JC. Mating behaviour of male orang-utans in the Kutai Game Reserve, Indonesia Gauri R. Pradhan,1,2* Maria A. van Noordwijk,1 and Carel van Schaik1. Model for the Evolution of Developmental Arrest in Male Orangutans 13