Skip to main content
Dryad

Effect of captivity on the vertebral bone microstructure of Xenarthran mammals

Zack, Ellianna1; Smith, Stephanie1; Angielczyk, Kenneth1

Research facility: Field Museum of Natural History
Published Apr 16, 2022 on Dryad. https://doi.org/10.5061/dryad.w3r2280rh

Data files

Apr 16, 2022 version files 15.21 GB

Click names to download individual files Select up to 11 GB of files for zip download

Abstract

Captive specimens in museum collections facilitate study of rare taxa, but the lifestyles, diets, and lifespans of captive animals differ from their wild counter- parts. Trabecular bone architecture adapts to in vivo forces, and may reflect interspecific variation in ecology and behavior as well as intraspecific variation between captive and wild specimens. We compared trunk vertebrae bone microstructure in captive and wild xenarthran mammals to test the effects of ecology and captivity. We collected μCT scans of the last six presacral vertebrae in 13 fossorial, terrestrial, and suspensorial xenarthran species (body mass: 120 g to 35 kg). For each vertebra, we measured centrum length; bone volume fraction (BV.TV); trabecular number and mean thickness (Tb.Th); global com- pactness (GC); cross-sectional area; mean intercept length; star length distribu- tion; and connectivity and connectivity density. Wild specimens have more robust trabeculae, but this varies with species, ecology, and pathology. Wild specimens of fossorial taxa (Dasypus) have more robust trabeculae than cap- tives, but there is no clear difference in bone microstructure between wild and captive specimens of suspensorial taxa (Bradypus, Choloepus), suggesting that locomotor ecology influences the degree to which captivity affects bone micro- structure. Captive Tamandua and Myrmecophaga have higher BV.TV, Tb.Th, and GC than their wild counterparts due to captivity-caused bone pathologies. Our results add to the understanding of variation in mammalian bone micro- structure, suggest caution when including captive specimens in bone micro- structure research, and indicate the need to better replicate the habitats, diets, and behavior of animals in captivity.