The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)

Associations between skeletal fractures and locomotor behavior, habitat use, and body mass in nonhuman primates


Anthropology, University of North Dakota

Friday 10:30-10:45, Galleria North Add to calendar

Falling injuries may be the most common cause of long bone trauma among nonhuman primates, yet the interrelatedness of trauma and positional behavior is poorly understood. In this study, 300 fractures affecting long bones from 1672 primates encompassing 22 taxonomic groups were examined macroscopically and radiographically. Among a spectrum of behaviors, larger, more arboreal primates commonly active higher in the canopy and/or primarily engaging in specialized locomotor modes all should exhibit increased fracture frequencies due to their greater risk of falling, or falling with more severe repercussions.

Fracture frequencies are highly correlated with locomotor mode. As expected, suspensory primates exhibit the highest fracture frequencies; however, leapers exhibit the lowest. Results of multivariate statistical analyses suggest that fracture patterns are most closely associated with locomotor mode and body mass, followed by arboreality and vertical distribution. When suspensory primates break a bone, it tends to be the humerus or femur. Smaller arboreal quadrupeds are more likely to fracture their tibia or fibula than another bone, whereas larger quadrupeds tend to fracture any long bone preferentially except for the tibia or fibula. Fracture occurrences in leaping primates tend either to involve the clavicle preferentially or are independent of location.

Associations revealed in this study appear to highlight the importance of risk avoidance in primate evolution. Skeletal trauma may affect reproductive fitness directly or incidentally. Consequently, primates should be under selective pressure to avoid the risk of obtaining fractures, developing behavioral and anatomical mechanisms to reduce the number and severity of falls from heights.

This study was partially funded by National Institutes of Health (P40 RR003640) and the Ohio State University.

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