Fancy Rat FAQs Should I get girls or boys? Both have their advantages. Boys tend to become lap rats when they mature and prefer to simply sit and be held. However, they are more likely to mark you with small drops of urine and are generally larger than females. Females usually do not mark and are generally smaller than males, but they are also more adventurous and active. Both have good and not so good qualities. It is up to you to decide which gender will be better suited to your lifestyle. ahead to next FAQ, "How should I choose my rats?" back to main FAQ page