Male and female chinchillas look alike, so can be difficult to tell apart. As you must keep chinchillas in pairs or larger groups, it’s essential to know whether your pets are male or female. 

How can you tell if a chinchilla is male or female? Males have a gap between the urethra and the anus, while in females, they are pressed together. Checking for this difference is known as ‘sexing’, i.e. determining the sex. The penis and the testes are not visible, while males have visible nipples like females, so this is the only difference. You can spot it by holding your chinchilla in a way that exposes its genitals. 

If you plan on getting more chinchillas in the future, this is an essential skill to have. Pet shop owners can mis-sex chinchillas which can result in accidental breeding among pairs. So, to learn exactly how to sex a chinchilla, read our guide below. 


Differences between Male and Female Chinchillas

The males and females of a species can look different to one another. This phenomenon is called ‘sexual dimorphism’. In some cases, the differences are minor; in other cases, they are major, like where the female is twice the size of the male. In some species, they are solely internal, while in others the differences can be seen from the outside.

There are examples of sexual dimorphism in chinchillas, although they are not immediately obvious if you don’t know what to look for. The table below lists these differences, before they are examined in more depth afterwards.

DifferenceDescription
AnatomicalA male has a penis and testes, while a female has a vaginal opening and a uterus. Externally, you can tell the difference because a male has a larger gap between its urethra and anus.
SizeFemales are larger in length and weight than males.
PersonalityThere is no difference between males and females in personality.
BehaviorFemales spray urine in certain circumstances while males don’t.

Determining the sex of your pet by looking at its anatomy is known as ‘sexing’. This is the surest way to tell whether your chinchilla is female or male.

Why Is It Important to Sex Chinchillas?

A chinchilla pair.
A chinchilla pair.

The sex of your chinchilla is important because these pets shouldn’t live alone. Chinchillas are social animals, so will thrive when kept with other individuals of the same species. While it is possible for a chinchilla to live alone, it won’t be happy. 

However, if you put a male chinchilla with a female chinchilla, the pair will mate. You will then have to take care of the kits, of which there will be between two and six. The pair will mate again and have more kits unless separated. This scenario is not recommended for novice owners: instead, you should only house male chinchillas with male chinchillas or female chinchillas with other females. To do so, you need to know the sex of each chinchilla you own. 


Anatomical Differences (Penis, Urethra, Nipples & Anus)

The easiest way to tell the difference between a male and a female chinchilla is through looking at their anatomies. Like other mammals, male and female chinchillas have different sex organs. A male chinchilla will have a penis and testes, while a female chinchilla will have a vaginal opening and a uterus.

Some of these differences are on the inside, while others are on the outside. If you know what to look for, you can spot these differences even as a novice.

Both male and female chinchillas have something called a ‘urethral cone’. This is what the chinchilla uses to wee. This is a small pointed protrusion which looks like a penis, and both males and female have one. However, in males, the penis is housed inside the urethral cone, while the females have a clitoris. Even if the penis is exposed, it looks the same as a female’s clitoris. 

Both male and female chinchillas also have anuses. Chinchillas use these to poop. As in other animals, the anus and urethra are not far away from each other. The chief visual anatomical difference between male and female chinchillas is that in males, the urethra and anus are further apart. In females, the two are so close together that they may look attached. In males, there is a gap. 

If you have ever had other rodent pets, you may be familiar with this idea already. Males and females of other rodent species have this same difference between them. 

Checking for Anatomical Differences in Chinchillas (Sexing Chinchillas)

Checking for these anatomical differences is known as sexing. This process is performed by breeders on chinchilla kits (babies), and by pet shop owners. This is done in the same way every time, which means that you can follow the same process quickly and easily. Here’s how it works:

  1. Lift your chinchilla according to good handling guidelines. Pick it up from below and provide a stable surface with your hands. For a more detailed guide, learn how to handle a chinchilla properly.  
  2. Place one hand around your chinchilla’s chest, underneath its forelegs. Place the other hand underneath its bottom. This should leave your chinchilla’s genitals visible. 
  3. Check for the gap between your chinchilla’s urethra and anus. A male will have a gap, while a female won’t. The gap should be hairless. 
  4. Compare this with the genitalia of a chinchilla you know to be either male or female. Either examine another chinchilla that you own, or pictures. 

If your chinchilla is not comfortable being held in this way, try to take a photograph of its genital area. This will let you compare its genital area to that of other males/females more easily. 

Unlike other animals, you can sex chinchillas from the time they are kits. Other species need to develop for longer before you can tell the difference, but this isn’t necessary for chinchillas. It is easier to sex adult chinchillas, however.

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Are Female Chinchillas Bigger than Males?

Kitchen scales
Kitchen scales with a bowl.

One way of telling if a chinchilla is male or female is assessing its size. This applies both to size and weight, and to both long and short tailed chinchillas. According to the Smithsonian, male chinchillas weigh only 500g compared to the female chinchilla’s 800g. 

Weigh your chinchilla to check its weight. Digital kitchen scales are the right size and are highly accurate. Begin by checking and noting the weight of a large bowl or tub, before weighing your chinchilla and the bowl together. Subtract the weight of the bowl from the overall weight for an accurate measurement. Some digital scales can do this for you; a bowl is necessary because otherwise, your chinchilla is unlikely to sit still. 

A captive chinchilla’s weight also depends on how it was raised. If it was raised optimally, i.e. with the right kind and amount of food, it will be larger than otherwise. As such, weight is not a guaranteed difference between male and female. 


Behavioral Differences in Male & Female Chinchillas

When sexing chinchillas, the surest way is to check their genitalia. But like in other animals, males and females can also behave differently. This means that even if a particular male is the same size as a female, you can still tell that it’s a male from how it acts.

The main difference is that females spray urine while males don’t.

Females Spray Urine, Males Don’t

Spraying urine is a common behavior in animals. In chinchillas, it is done when frightened or angry as a defense mechanism rather than to mark territory. If you ever surprise your pet, or it hears a loud noise, you may notice this behavior. 

Bear in mind that this is a generalization. It is not unheard of for males to spray; but it is much less common. And when a male sprays, it is less strong than the equivalent spray of a female. So, if one of your pets sprays all the time while the other doesn’t at all, they are probably female and male respectively. 

Female vs Male Personalities in Chinchillas

As for personality, this is another common difference in pets. In certain species, females are more friendly while males are more aggressive, for example. But this isn’t the case for chinchillas: male and female chinchillas do not have recognizable personality differences.

Each chinchilla has a unique personality which is not dependent on its sex. One chinchilla may be more defensive than another, or another chinchilla might enjoy time spent with its owner more than another. Anybody who has owned multiple chinchillas will say that they have personalities. But these are not in any way dictated by sex.


Can Chinchillas Change Gender?

A commonly reported problem occurs when two chinchillas are kept together. The owner will be convinced that both are female or that both are male, and may even have been told so by the pet shop owner. But before long, the pair begin to mate and one becomes pregnant.

Chinchillas categorically cannot change gender, but cases in which a male chinchilla is thought to be female (or vice-versa) are common.

There are many reasons why this occurs:

  1. Some pet shop owners are not as experienced with animals as they make out
  2. Chinchillas are exotic animals, which makes it more likely that even experienced pet shop owners make mistakes
  3. Your pet or pets may have been mislabelled when you bought them
  4. You may have misheard or misunderstood when the pet shop owner told you one was male and one female

Whatever the case, the issue must be something other than the chinchillas changing gender, as this is impossible.

Is My Chinchilla a Boy or a Girl?

If you aren’t sure whether your chinchilla is male or female, look at its anatomy. But if you still can’t tell, ask an expert to sex the chinchilla for you. 

Your best bet is a vet who deals in small animals/exotics. Most vets are generalists, and will look at any animal you bring to them; other vets look specifically at small pets like rodents, while others specialize in all exotic animals. It’s a specialist who is the best option, although all vets should sex a chinchilla without issue.

If for whatever reason you cannot consult a vet, talk to a pet shop owner or a chinchilla breeder. They may even sex your chinchilla for free, while a vet would charge. 


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