To compare the ways in which hand reared and non hand reared Pongo pygmaeus (Bornean Orangutans) react to enrichment by identifying the pre and post enrichment behaviours.
Subject being studied:
Four Pongo pygmaeus
1) RAMON: Male, 1998
2) VICKY: Female, 1984
3) SUMMER: Female, 2002
4) CHERIE: Female, 1997
Sampling technique and data collection:
The sample was systematic (quantitative) with a sample size of 4 subjects.
It was an instantaneous sample, with the behaviours of the individual recorded at 15 second intervals.this was recorded on an ethogram for 10 minutes.
The data suggests that the Pongo pygmaeus that were hand-reared interact more with the enrichment. The two subjects Vicky and Ramon showed a large increase in feeding and enrichment behaviours. In terms of percentages, Ramon’s interactions with enrichment increased from 0% to 64% whilst Vicky’s increased from 0% to 39%. They were therefore largely occupied. On the other hand, post enrichment the mother reared Pongo pygmaeus had a 0% interaction with the enrichment. Cherie spent 84% post enrichment resting and Summer spent 50% post enrichment testing.
A possibility is that the hand-reared are used to human intervention and constructed enrichment, they are therefore more dependent on it.
However, Summer and Cherie’s mother is Vicky so it is expected that they would have learned behaviours from her. There are also other factors that need to be considered. Ramon is the dominant male in the social structure, so the younger Pongo pygmaeus may have been avoiding the enrichment due to Ramon’s presence. They may return to it later as my data only covered a 10 minute time period, this is a major limitation.
In addition to this, awareness of the enrichment and therefore the location of it affects the Pongo pygmaeus’ interaction with it.
The limited viewing areas and movement between inside and outside enclosures also created voids in the data collection as the subjects were out of views.
The sample size of 4 may not be representable of hand-reared and mother-reared Pongo pygmaeus. The study should be repeated with different enrichment types too.