Male rats and female rats have many similarities, but also several distinct differences. It’s best to keep only one gender at a time, or to keep a mixed sex colony with all rats of one or both genders spayed or neutered. Most rat fanciers prefer one sex of rat over the other. If you’re considering your first pair of rats, deciding between two males or two females can be tough. Here’s some information to help you choose.
Male rats are much larger at maturity, on average, than female rats. My largest male rat is over 800 grams, while my female rats average 400-500 grams, with the smallest girl under 300 grams. Male rats are also more prone to obesity in old age, and may balloon to over 1,000 grams if their diet is not well-monitored!
The large size of male rats may be a benefit if your household includes children. Kids should always be supervised when handling pets, but an escaped 800-gram squishy buck is probably less likely to get into trouble than an excited 300-gram doe, should a child open the cage or drop a rat.
By contrast, the small size of females is advantageous in some living situations. All rats need at least two cubic feet of cage space per rat. However, females can use smaller wheels, hammocks, igloos, and other items. They also tend to prefer a taller cage with more levels and climbing room, rather than a wide cage with lots of room to sprawl.
All young rats are energetic and playful. However, from middle age onward, males and females have distinctly different personalities. Most male rats tend to be laid-back and more interested in staying on a lap for a long petting session, while female rats are explorers who love to play. Of course, there are exceptions to every rule. Some male rats stay bouncy and squirmy into old age. Some females love nothing more than a good cuddle. But, in general, male rats are more mellow while females are more playful.
Both bucks and does need daily handling and playtime. However, rat-proofing a playroom might be more difficult if you have female rats. Simple measures like removing cords and sealing any holes in the wall near the rats’ play area aren’t always enough. A particularly determined female rat looking for something nice to use for nesting or to add to a stash can get into all sorts of interesting places. My female rats once stole and shredded my energy bill. Somehow, I don’t think the customer service representative at the call center believed my excuse for requesting a duplicate bill!
Males also present unique challenges for the owner. They tend to enjoy attention and cuddling, but particularly mellow bucks might not get enough exercise without encouragement. I find that my boys will play until they’re out of breath if I get down on the floor with them and tickle them, then let them chase my hand across the floor.
One other potential disadvantage to buck ownership is hormonal aggression. A well-bred male rat will rarely become territorial or aggressive, but it’s always a possibility. Neutering usually solves aggression between bucks. If for some reason you lack a vet that you can trust to neuter a rat if necessary, reconsider rat ownership; a competent vet is essential. However, hormonal aggression can be annoying and frustrating for rat and owner until a neuter is scheduled. If you simply can’t imagine coping with your rats fighting, does may be a better choice.
Both male and female rats have unique health concerns. Male rats may develop testicular cancer. Removing citrus fruits from their diets and feeding a healthy variety of fresh foods can help reduce the likelihood of these conditions. Males are also more prone to hind-leg degeneration, a condition common in old age that can cause varying degrees of hind leg weakness, from a wobbly gait to complete paralysis of the rear limbs.
Female rats are very prone to develop mammary tumors. By some estimates, as many as half of all does will develop a mammary tumor in their lifetime. Spaying at a young age can decrease the risk of mammary tumors, as well as eliminate the risk of pyometra, another fairly common and life-threatening condition. Pyometra is an infection of the uterus. If not treated promptly, pyometra will cause death.
Some people feel that male rats smell much worse than females. I personally don’t notice much of a difference in smell between my males’ cage and my females’ cages. Males are harder to litterbox train, but with diligence and a large enough litterbox, both genders can be taught to use a box fairly reliably.
Bucks do, however, dribble. They leave a trail of urine whereever they go. Some females also use urine to scent mark their territory, but all males do it. They also may pee on you, each other, their food, their favorite hammock, or just about anything nearby. If you have snow-white carpets, rats probably aren’t the pets for you. But if you simply prefer to decrease the net amount of urine on your clothing, females may be a more pleasant pet.
However, females do come into heat approximately every four days. Some dominant females will become very excitable during heat cycles and attempt to initiate mating with humans. If that pushes one of your gross-out buttons, males may be the best choice.
Don’t worry too much if you can’t decide between male and female rats. If you’ve done your homework and chosen a good rescue or breeder, that person will be able to guide you toward individual rats who are a good fit for your lifestyle. Males and females need the same amount of space, the same amount of handling and attention, and the same diet (except that males should avoid citrus). You’ll come to love whichever rats you choose.
When it comes right down to it, if you find that rats are suited to your family and lifestyle, you’ll have plenty of chances to try out each gender or even keep a mixed-sex colony by spaying or neutering some of your rats. Rats’ short lives are the biggest disadvantage to rat ownership, but also mean you’ll have many opportunities to own different types of rats. Besides, they’re like potato chips: You can’t have just one, and I bet you can’t stop at just two for very long!