Radiographic Assessment of Spinal Degeneration in Vervet Monkeys (Chlorocebus aethiops): Prevalence, Patterns, and Relevance to Primate Aging Models.

Degenerative changes of the vertebral column are common in aging primates; however, patterns of spinal osteopathy remain poorly characterized across small- and medium-bodied primate species, limiting comparative interpretations of skeletal aging. Expanding assessments beyond well-studied taxa provides a broader framework for understanding primate musculoskeletal senescence and generates baseline data essential for interpreting vertebral degeneration in wild and semi-free-ranging populations, where ecological and life-history factors influence skeletal aging. We investigated age-, sex-, and body mass-related variation in vertebral osteopathies radiographically assessed in 70 captive vervet monkeys (Chlorocebus aethiops). Osteophytes were the most frequent lesion (78.6%), followed by discopathy (12.7%), syndesmophytes (2.9%), and scoliosis (1.4%). Age was the primary predictor of osteophyte presence across spinal regions, whereas sex and body mass showed no significant independent effects. In contrast, total osteophyte scores were significantly higher in older, heavier individuals, and females exhibited slightly higher adjusted scores than males. Nonlinear regression models revealed distinct age-related trajectories among spinal regions, with osteophytes emerging earliest in the lumbar spine (~ 1 year), followed by the cervical (~ 7 years) and thoracic (~ 9 years) regions. These findings characterize the natural history of spinal degeneration in vervet monkeys under captive conditions and provide comparative baseline data for distinguishing age-related changes from pathological alterations in both captive and free-ranging primate populations.