Postcranial Skeletal Differences in Free-Range and Captive-Born Primates.

Area of Science:

• Primate morphology
• Comparative anatomy
• Evolutionary biology

Background:

• Skeletal morphology is crucial for evolutionary, genetic, developmental, physiological, and functional research.
• Captive-born individuals are often included in studies due to sample size, demographic, or conservation constraints.
• Captivity can induce physical, physiological, or behavioral changes affecting skeletal form.

Purpose of the Study:

• To assess postcranial skeletal form differences between free-ranging and captive-born primates.
• To compare these differences in two species: Macaca mulatta (macaques) and Saguinus oedipus (marmosets).

Main Methods:

• Recorded 24 skeletal dimensions from various bones (scapula, limbs, innominate) in adult free-ranging and captive-born macaques and marmosets.
• Assessed age of epiphyseal closure in immature captive-born macaques.
• Utilized analysis of variance and principal component analyses to detect significant differences.

Main Results:

• Significant differences in postcranial size and shape were observed between free-ranging and captive-born individuals within each species.
• Free-ranging macaques were larger than captive-born macaques, though this pattern was not consistent in marmosets.
• Shape differences were notable throughout the skeleton, with the scapula showing particular prominence.

Conclusions:

• Captivity significantly influences primate postcranial skeletal morphology.
• Developmental timing, nutrition, and physical activity in captivity contribute to observed skeletal variations.
• These morphological differences must be considered when incorporating captive-born primates into morphological or evolutionary studies.