Other females within the social group may assist in the birthing process and tend to the newborns. Pups are born with their eyes open; they will begin to leave the nesting area at about 3 days of age. Babies are weaned around 5 to 6 weeks and reach sexual maturity at about 6 to 9 weeks. A female can conceive throughout the year and may produce up to 9 litters in a year. Lifespan for spiny mice is 4 to 7 years. The mother is able to become pregnant right after birth. One species of spiny mouse was recently discovered to have a menstrual cycle which would make them important as a model organism to study menstruation and reproductive disorders, as Mus musculus, the common laboratory mouse, does not menstruate. Diabetes Captive housing of spiny mice in the mid-1960s uncovered their sensitivity to developing diabetes. That is, spiny mice were kept as pets and maintained on bird food consisting of fat-rich pumpkin, sesame, and sunflower seeds. This diet was associated with obesity, glucosuria, and ketosis. Further studies, in the Institute of Biochemistry in Geneva, revealed that spiny mice manifest low insulin secretion capacity, low response to glucose, and faint first-phase insulin release, despite pancreatic islet hypertrophy and hyperplasia. Notably, they do not show the common symptom of insulin resistance. Also, A. russatus is not known to develop symptoms of diabetes under a similar diet. Autotomy and tissue regeneration All studied species of spiny mice, Acomys kempi, A. percivali, A. cahirinus, A. dimidiatus, and A. russatus, are capable of autotomic release of skin upon being captured by a predator. To date, spiny mice are the only mammals known to do so. They can completely regenerate the automatically released or otherwise damaged skin tissue – regrowing hair follicles, skin, sweat glands, fur and cartilage with little or no scarring. It is believed that the corresponding regeneration genes could also function in humans. In a research article published on May 16, 2017, in eLife, a team from the University of Kentucky described the role of macrophages in epimorphic regeneration. The subtype of macrophages found in African spiny mice produces a different immune response than the subtype that elicit scarring. Disease Because spiny mice are highly prevalent throughout Africa and rodents are known to be carriers of disease, an investigation into whether spiny mice may carry disease was done in Egypt in 1912. In