Bailey, Kathryn Elizabeth (2018-12). Locomotion of the Red-Shanked Douc Langur (Pygathrix Nemaeus) in the Son Tra Nature Reserve, Vietnam. Doctoral Dissertation. Thesis uri icon

abstract

  • This study aims to compile data on the locomotor behavior of the red-shanked douc langur (Pygathrix nemaeus). This dissertation focused on establishing the historical context for primate locomotion studies and provides a brief introduction to the odd-nosed monkeys, of which Pygathrix is a member. Furthermore, this dissertation contributes locomotor and some anatomical data relating to the arm-swinging capabilities of the redshanked douc langur. Landmark data was used to identify elements of scapular shape to infer locomotor behaviors. I used shape data on the scapula of the douc langurs to identify if the three species of Pygathrix share a similar scapula shape. There was no statistically significant difference in scapular shape between the three species, thereby lending some support that all are likely moving in similar ways. I also used landmark data to compare Pygathrix (all three species) to quadrupeds and brachiators and found Pygathrix to be significantly different from both. Landmark data was also used to calculate the straight-line distance between the distal most portion of the acromion process and the center most point of the glenoid fossa to see if this distance could predict locomotor behaviors. For species that routinely use their arms for locomotor purposes (i.e. brachiators, quadrupeds, and armswingers) there was a significant difference in distance between the groups. When incorporating bipedal individuals, there was less of a significant effect. In addition I looked at behavior data from the Son Tra Nature Reserve in Da Nang City, Vietnam to identify elements of wild locomotion. I looked at body size characteristics to determine if heavier individuals were arm-swinging more or less than lighter individuals. This study showed that in fact, the lightest individuals (juveniles) used arm-swinging the most, followed by sub-adults, adult females, adult females carrying babies, and then adult males. Finally, I identified environmental variables and how those variables correlate with the red shanked douc's locomotion. The results of this study indicated that doucs prefer to arm-swing in old-growth forest, in the main canopy, and on horizontal and medium sized substrates.
  • This study aims to compile data on the locomotor behavior of the red-shanked douc
    langur (Pygathrix nemaeus). This dissertation focused on establishing the historical
    context for primate locomotion studies and provides a brief introduction to the odd-nosed
    monkeys, of which Pygathrix is a member. Furthermore, this dissertation contributes
    locomotor and some anatomical data relating to the arm-swinging capabilities of the redshanked
    douc langur.
    Landmark data was used to identify elements of scapular shape to infer locomotor
    behaviors. I used shape data on the scapula of the douc langurs to identify if the three
    species of Pygathrix share a similar scapula shape. There was no statistically significant
    difference in scapular shape between the three species, thereby lending some support that
    all are likely moving in similar ways. I also used landmark data to compare Pygathrix (all
    three species) to quadrupeds and brachiators and found Pygathrix to be significantly
    different from both. Landmark data was also used to calculate the straight-line distance
    between the distal most portion of the acromion process and the center most point of the
    glenoid fossa to see if this distance could predict locomotor behaviors. For species that
    routinely use their arms for locomotor purposes (i.e. brachiators, quadrupeds, and armswingers)
    there was a significant difference in distance between the groups. When
    incorporating bipedal individuals, there was less of a significant effect.
    In addition I looked at behavior data from the Son Tra Nature Reserve in Da Nang
    City, Vietnam to identify elements of wild locomotion. I looked at body size
    characteristics to determine if heavier individuals were arm-swinging more or less than
    lighter individuals. This study showed that in fact, the lightest individuals (juveniles) used
    arm-swinging the most, followed by sub-adults, adult females, adult females carrying
    babies, and then adult males. Finally, I identified environmental variables and how those
    variables correlate with the red shanked douc's locomotion. The results of this study
    indicated that doucs prefer to arm-swing in old-growth forest, in the main canopy, and on
    horizontal and medium sized substrates.

publication date

  • December 2018