You do NOT need to read this section. This section is provided for your personal benefit. I still highly recommend reading this page for your own education.


A common question people ask themselves is whether they want boys or girls. Since you should only keep one sex, this is an important decision you must make if you don't already have rats at home. This section will cover the main differences and the possible problems of each sex.


Overall, the temperament of males tend to be affectionate, lazy, and mushy. Males are considered "lap rats" more often than not because they are more likely to sit still in your lap for cuddles and attention.


  • Mushy and more likely to be a lap rat
  • Bigger if you like big rats
  • Healthier than females, far less likely to get tumors


  • Dominance can turn into aggression requiring neutering
  • Tend to mark more than females
  • Bigger rats will eat more food and need a bit more space
  • Have big ol' balls that can be unsightly
  • Can have a slight odor


Girls are curious, engaging, and humorous. They enjoy exploring, using a wheel, and they tend to be more playful. Girls are considered more adventurous and are less likely to sit in your lap for out of cage time. They are naturally more independent compared to boys, but are still affectionate.


  • Playful and humorous - can be more entertaining
  • Tend to be smaller than boys so they eat less and take less space
  • Less chance of aggression problems
  • Don't mark as much as boys
  • Can have less natural odor


  • Tumors are a bigger issue in girls
  • May not enjoy sitting still for cuddles on the couch - usually want to roam
  • Frequent heats (reproductive cycles) can make them high strung at times


Both sexes mark, both sexes have tumor risk with females at a much higher risk, both really enjoy affection with girls wanting to explore more than boys. Both have risk of dominance problems with boys at a higher risk.

How to process these pros & cons

If you want a mushy rat that is more likely to chill on the couch with you and melt in your hands, go with boys. Marking is a issue in both sexes so there is not much gain there with females and altering will usually solve issues with aggression IF that even ends up being a problem. If you want rats who are more playful, curious, ferret-like, and adventurous then go with girls. There is the higher risk of tumors, but proper diet and environment will help ensure a long and healthy life.

Aggression in males

Aggression can be a problem with mainly boys. While they are healthier than females, they CAN develop aggression as they age. Good breeders such as myself do our best to breed this problem out of our lines. With my lines, aggression is not typically an issue. I frequently move around my males and females over time. Dominance occurs with my adults, but I rarely have issues with injuries occurring. Dominance is acceptable behavior and will likely occur in both sexes. Normal and acceptable dominance includes boxing (both rats standing on their hind legs and getting in each others face), "crab walks" (stiffening and bumping the other rat with their bum), squeaking/vocalizing, and pinning (one pins down the other). These dominance behaviors are usually nothing to worry about. They usually occur during introductions and when the hierarchy is being established or questioned. Aggression is different than dominance. Signs of aggression are very frequent arguments, loud screaming, chasing, and ultimately biting. A common motto with rat owners is "no blood, no foul." Most, myself including, agree with this statement. If there is too much chasing, arguing, and mainly nipping/biting then you may need to consider neutering the aggressor. This usually stops the problem. Housing the aggressive rat alone should be a LAST resort meaning that it should only be done if neutering doesn't work. The rat must be at least 3 months old to be neutered and it MUST be done by a rat experienced vet.

Tumors in females

Tumors can happen in males, but they are far more of a problem in females. Luckily, proper diet, good genetics, and proper environment help keep them at bay. Unhealthy treats like candy, pizza, etc will increase the risk for problems; fatty, sugary foods are bad for both rats and people. Most tumors in rats are not cancerous so they are often successfully removed by a vet.


When getting a new hamster, choosing whether you want a male or female can be an important decision. There are differences between each sex which are noted below for your reference.



  • No heats
  • Can be a little more laid back
  • The long haired gene is fully expressed on males only


  • The long haired hamsters can have issues with certain bedding tangling in their long fur
  • Large testicles, which some find unsightly



  • Can be more active and entertaining
  • If you want a short hair, both long haired and short haired females look like short hairs, but with a slightly fuller looking coat
  • No unsightly testicles


  • If you want a long hair, the long hair gene barely expresses on females
  • Heats occur every 4-5 days which cause a fishy smell near her vulva