Brogan Stewart

Concordia University
Ph.D. candidate

Supervisor: Sarah E. Turner
Start: 2019-09-01
End: 2023-08-31
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Using fractal analysis to determine if physical impairment in Japanese macaques (Macaca fuscata) alters behavioural movement complexity
Animals respond to stressors in a variety of ways. Research has demonstrated that chronic stress influences animal behaviour in captivity, for instance, a high percentage of captive individuals display stereotypic behavioural patterns such as pacing or wall licking. Irregular movement sequences are more difficult to assess in free-ranging and wild animals, however free-ranging contexts also pose regular challenges of physical wellbeing and optimal movement ability. A population of Japanese macaques (Macaca fuscata) on Awaji Island, Japan, exhibits very high incidences of congenital limb malformations that cause physical impairment. This circumstance provides a rare opportunity to observe behavioural responses to disabilities in a free-ranging primate population. Previous work by Dr. Sarah E. Turner and colleagues suggested that disabled individuals in the population spent a similar amount of time engaged in locomotion compared to non-disabled controls. Japanese macaques live within social groups; therefore, their movement activity budgets are constrained by group movement patterns. Fully understanding and quantifying the costs of these disabilities remains a challenge. Animals’ responses to physical challenges are not always discernible through direct observation alone; and subtle variation in movement complexity may provide a useful measure for quantifying the costs of disability. Fractal analysis is a promising method for quantifying impairment. This method measures subtle variations in the complexity of movement behaviour patterns and sequences. In their study, Dr. Andrew J. J. MacIntosh and colleagues showed that parasite load and other health stressors were associated with a reduction in the complexity of locomotion behaviour in Japanese macaques. Altered behavioural complexity, whether an increase or a loss, negatively impacts the individual, since it is a deviation from their optimal movement patterns. Complexity of behavioural sequences may be subtly and negatively affected by physical impairments. I plan to test the hypothesis that impairment caused by congenital limb malformations will alter the complexity of movement behaviours for disabled monkeys under free-ranging conditions. In order to test this hypothesis, I plan to collect continuous-time focal animal follow data on a sample of disabled monkeys and nondisabled controls at the Awajishima Monkey Center, using methodological protocols that have been applied in previous research at this site. I plan to learn how to conduct fractal analysis in collaboration with colleagues at the Kyoto Primate Research Institute, applying the fractal analysis methods developed by Dr. MacIntosh for behavioural data. The majority of studies on behaviour do not take complexity into consideration. Fractal analysis is a valuable tool for connecting behavioural complexity and environmental uncertainty. Insight into sequential complexity of animal behaviour is critical for understanding behavioural flexibility and resilience in changing environments.


Primate, Fractal Analysis, Animal behaviour, behavioural complexity, Disability, Japanese macaque, ecology