 Like other stingrays , the plain maskray is viviparous with the developing embryos sustained to term by histotroph ( " uterine milk " ) produced by the mother . <unk> females have a single functional ovary and uterus , on the left . Litter size is one or two ; the newborns measure 12 – 14 cm ( 4 @.@ 7 – 5 @.@ 5 in ) across . Males and females reach sexual maturity at disc widths of 20 – 21 cm ( 7 @.@ 9 – 8 @.@ 3 in ) and 18 – 19 cm ( 7 @.@ 1 – 7 @.@ 5 in ) respectively . The maximum lifespan is estimated to be 9 years for males and 13 years for females . 
