Covariation between entheseal changes and cross-sectional properties of reindeer long bones:considering bone functional adaptation as partial contributing factor

• Main Authors: Niinimäki, S. (Sirpa), Salmi, A.-K. (Anna-Kaisa)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2021
• Subjects: Bone biomechanical properties; Physical activity; Rangifer tarandus fennicus; Rangifer tarandus tarandus; Reindeer; Rangifer tarandus
• Online Access: http://urn.fi/urn:nbn:fi-fe2021070841244

Abstract Entheseal changes and bone cross-sectional properties are used as skeletal activity markers for different animal species, although most studies are targeted on humans. While there is compelling evidence on the association between activity and bone cross-sectional properties, studies on association of entheseal changes to activity have presented more contradictory results. In previous research, covariation between entheseal changes and bone cross-sectional properties is considered a possible result of common underlying factor. However, these studies are performed predominantly on human material. We provide beyond-species scope by studying this covariation in reindeer skeleton. The results will provide platform for discussing bone functional adaptation pathway in which activity modifies entheseal appearance. The material are wild forest reindeer, domesticated free-ranging reindeer and zoo reindeer of Northern and North-East Finland. We found that bone formation in most studied entheses (25 out of 27) were associated with increased values in bone cross-sectional properties and proxies of bone/body size. Features of bone resorption, when significant, were also associated with increased values in bone cross-sectional properties and bone/body size. We conclude that as entheseal changes were associated with bone cross-sectional properties and bone/body size, the observed variation at reindeer entheses likely reflects skeletal robusticity. While causal factors resulting in association between skeletal robusticity and entheseal appearance cannot be evidenced, bone functional adaptation can be hypothesized as at least a partial contributing mechanism to entheseal appearance.