Being able to distinguish between male and female residents at your animal organization is important for many reasons, but in particular because one of the most critical things that define a farmed animal sanctuaryAn animal sanctuary that primarily cares for rescued animals that were farmed by humans. (versus a petting zooAn organization where animals, either rescued, bought, borrowed, or bred, are kept, typically for the benefit of human visitor interest.) is that sanctuaries do not and should not breed animals or allow their residents to become pregnant or reproduce accidentally. Thankfully, unlike some other farmed animalA species or specific breed of animal that is raised by humans for the use of their bodies or what comes from their bodies. sanctuary species, it’s very easy to tell the difference between male and female pigs once you know what you are looking for.

How To Differentiate Between Male And Female Pigs

To differentiate between male and female pigs, you must examine their external reproductive organs. The easiest and most reliable way to do this is to look for the presence or absence of a vulva. To do this, you must look under the individual’s tail. Depending on their breed and whether or not their tail has been docked, you may need to gently lift or move their tail. (As a side note, tail docking is a cruel practice in which a portion of the tail is removed without anesthesia or analgesics. This practice is unacceptable but routinely performed on large breedDomesticated animal breeds that have been selectively bred by humans to grow as large as possible, as quickly as possible, to the detriment of their health. piglets in agricultural settings.)

At The Open Sanctuary Project, unacceptable means that we cannot condone (or condone through omission) a certain practice, standard, or policy. See a more detailed explanation here.

Underneath the tail base is the anus. If the individual is a male, the anus is all you will see under the tail, whereas in females, you will also see the vulva just below the anus, as shown in the illustration below.

In addition to the presence of a vulva in females, another anatomical difference between males and females is the presence of the prepuce (which houses the penis) in males. This is located on the midline of their abdomen. However, looking for the prepuce is not always an obvious or reliable way to differentiate between males and females. Depending on the breed and age of the individual, the prepuce may not be obvious from afar. Additionally, an umbilical hernia may be confused for a prepuce. Therefore, we always recommend also checking for the presence or absence of the vulva when determining if a pig resident is male or female. In the illustrations below, you can see that the male pig (left) has a prepuce whereas the female pig (right) does not. However, remember that in some individuals the prepuce may not be as obvious as in the illustration below. Also, note that both males and females have nipples.

Depending on the circumstances, instead of trying to visualize the vulva (or confirm its absence), it may be easier to observe the individual urinate. Because the urethral opening in females (which is part of the vulva) is located under the tail, you will note that when they urinate, the urine arcs out in a stream behind them. Since the urethral opening in males is on their underside, you will note that the urine comes out from underneath them. Be aware that there may be rare instances where a male has previously undergone surgery to create a new urethral opening under the anus (perineal urethrostomy), and therefore, it is always recommended to confirm an individual’s sex by checking to see if they have a vulva or not.

Other Physical Differences And Similarities Between Males And Females
A pig’s size and body shape will vary depending on their breed, age, and health, so you cannot determine a pig’s sex simply by their size or shape (nor can you make assumptions about pregnancy based on belly size alone). A key difference you may note between male and female pigs is the presence of long tusks in males. However, this is not a reliable indicator of sex because there are a variety of reasons why a male pig may not have long tusks – their absence is not a guarantee the individual is female. A male may not have long tusks due to accidental breakage or previous tusk trimming, and young males may not yet have obvious tusks.

Determining If The Individual Has Been Spayed Or Neutered

Spaying and neutering pig residents is an essential part of their care, so long as your veterinarian deems them healthy enough to undergo the procedure. Therefore, in addition to determining their sex, you also want to determine if they are intact (i.e., have not been spayed or neutered). If a male is intact, their testicles may or may not be very obvious depending on their breed and age. Be aware that a pig’s scrotum is held closer and tighter to the body than that of a goat or cowWhile  "cow" can be defined to refer exclusively to female cattle, at The Open Sanctuary Project we refer to domesticated cattle of all ages and sexes as "cows.". Rather than hanging down between their back legs, a pig’s scrotum protrudes behind them, as shown in the illustration below.

All intact males should be neutered as soon as your veterinarian deems it appropriate. While the obvious presence of testicles is a clear indication an individual is intact, be aware that cryptorchidism (where one or both testes have not descended into the scrotum) is possible. If an individual who appears to have been neutered is behaving as though they are intact, be sure to discuss the possibility of cryptorchidism with your veterinarian. You can read more about having pigs neutered (including those with cryptorchism) here. 

Determining if a female has been spayed is not as easy. Depending on the pig’s age, you may observe physical and behavioral changes such as confrontationalBehaviors such as chasing, cornering, biting, kicking, problematic mounting, or otherwise engaging in consistent behavior that may cause mental or physical discomfort or injury to another individual, or using these behaviors to block an individual's access to resources such as food, water, shade, shelter, or other residents. behaviors, mounting, swelling of the vulva, and vaginal discharge when intact females go into estrus (“heat”). Pigs go into estrus approximately every three weeks. While you may be able to detect scars suggesting an individual may have been spayed, we always recommend having the individual evaluated by a veterinarian to determine if she has been spayed or not. Due to the risk of reproductive diseases, we recommend all female pigs be spayed when your veterinarian deems it appropriate. You can read more about spaying pigs, including the different types of procedures that may be recommended, here.

SOURCE:

Male Or Female? | California Potbellied Pig Association

Reproductive System | The Pig Site (Non-Compassionate Source)

Reproductive Cycles In Pigs | Animal Reproduction Science(Non-Compassionate Source)

Non-Compassionate Source?
If a source includes the (Non-Compassionate Source) tag, it means that we do not endorse that particular source’s views about animals, even if some of their insights are valuable from a care perspective. See a more detailed explanation here.