Skin Development in the Gray Short-Tailed Opossum (Monodelphis Domestica) - From Skin Respiration to Thermoregulation

The study examines skin development in 36 gray short-tailed opossums (Monodelphis domestica) from neonate to adult, highlighting the transition from skin respiration to thermoregulation. Initially, the opossum's skin is thin and undifferentiated, facilitating gas exchange through a dense capillary network. This capillary volume density decreases significantly in the first postnatal week, while the skin diffusion barrier increases. By day 28, hair follicles, sweat glands, and subcutaneous fat begin to form, marking the onset of thermoregulation. The skin thickens from 58 μm at birth to 726 μm by day 35. Concurrently, the cardiac and respiratory systems mature, with the lung reaching the saccular stage by day 7, supporting the organism's respiratory needs. The study underscores the functional shift in skin from gas exchange to thermoregulation during postnatal development.