
Giant eggs helped early mammal ancestors weather the Great Dying
New ESRF X-ray CT analysis of a Lystrosaurus egg and embryo shows these proto-mammals laid large, soft-shelled eggs; the precocial hatchlings could feed themselves and reproduce, and the eggs’ low surface-area-to-volume ratio would resist desiccation, helping Lystrosaurus surge after the mass extinction and dominate post-extinction ecosystems.












