Maturation of the two sexes takes differently long: female G. spixii have an open vagina when they are approximately eighty days old while the testicular descent is completed in male G. spixii at around one hundred thirty-five days old. Males and females in this species are aggressive to each other. Paternal care is rarely remarkable.
The sexual maturation of both sexes differs in duration: female G. spixii have an open vagina at approximately eighty days old, while male G. spixii's testicular descent is completed around one hundred thirty-five days old.  Males and females exhibit aggression towards each other. Paternal care is rarely observed.