Gerbil Gerbillinae

Gerbil names a whole subfamily, Gerbillinae; the animal kept as a pet and used in laboratories is the Mongolian gerbil, Meriones unguiculatus, and every figure here refers to it. It is an arid-adapted rodent that produces concentrated urine and has a low water turnover, voluntarily drinking only about 4 to 10 mL per 100 g of body weight each day, so water intake and hydration need interpreting against desert physiology rather than against a rat. Adults are small, quoted between 50 and 135 g, about 10 cm long with a furred tail of similar length that must never serve as a handle, because the skin slips and the exposed tail has to be amputated. Gestation is 24 to 26 days and breeding begins at roughly two to three months. Two conditions dominate practice. Spontaneous seizures, provoked by handling or a novel environment, start at two to three months, worsen to about six months and then decline; they are reported in 20 to 40 per cent of gerbils, are uncommon in many pet lines, and rarely kill. Second, the ventral midline marking gland, a sebaceous scent organ in both sexes, turns neoplastic in older animals, benign or malignant, and frequently ulcerates.