It has also been hypothesized that osteophagy is a practice necessary for the maintenance of desert tortoise shells. This parallels the phenomenon of osteophagy in birds, in which snail shells are ingested by egg-laying females to supplement the increased calcium needed for eggshell formation. Therefore, it would be expected that the increased physiological needs of juvenile and gravid female tortoises would also increase mineral demands and promote ingestion of bones, stones, and soil. Alternatively, the need to consume supplemental minerals may serve the purpose of detoxifying plant compounds, or may serve other purposes not related to nutrition such as to dislodge gut parasites.
