Don't Rely -- VERIFY!​

No matter what anyone tells you, verify the sex of your guinea pigs BEFORE you put them together -- especially if you got your guinea pig from a pet store. Pet stores are notorious for getting it wrong frequently -- all kinds of pet stores -- from Mom and Pop stores to the big chains, including the so-called 'same-sex-only' stores. Don't take chances. They will happily sell you (unknowingly or not) a male and a female, and will blithely tell you it's two females. They will also (unknowingly or not) sell you a pregnant female. If you end up with more mouths to feed, all the better for the store. That's the name of the game in the first place -- animals to feed and care for keeps you coming back for profitable consumables and other accessories. If you cannot confirm the sex yourself, take them to a vet or a rescue to verify. THIS IS JOB ONE. You have no idea of the monumental and extremely expensive messes people get themselves into by ignoring this one important step. And everyone is human. Everyone makes mistakes -- veterinarians, shelter employees, rescuers, individuals trying to rehome their pets -- everyone. We all have stories. You MUST take responsibility to confirm the sex of your guinea pigs.

Tempted to allow just one litter?​

So You Think You Want Babies? Your caging decisions alone become much more complicated and expensive. We share the experiences of many others who thought the same thing and we discuss the possible results and what they entail. If you allow animals to breed, even once, you are a breeder -- how often or what your motivation is -- doesn't matter. Breeders are to blame for half of the pets killed at shelters. People who buy from pet stores and breeders rather than adopt are responsible for the other half. It's about the inescapable supply and demand equation. Every bred pet takes up a home that could have gone to one in need. Every bred pet indirectly adds a taxpayer burden and adds to the personal burdens of rescuers. You say you have homes lined up for your babies? Changes nothing. Those are homes that could have gone to saving a life.

Adopt and rehome responsibly​

No female needs to have a litter. Yet, some believe that pets have a biological, religious or moral imperative to breed. We do not need to project our personal beliefs onto innocent animals. Any female guinea pig can live a great life just fine without procreating or experiencing motherhood.

And no, you do not need to 'carry on the line' of your favorite guinea pig -- or any pet for that matter. Appearance and personality can vary greatly in litters of guinea pigs. Honor any guinea pig by adopting and saving a life.

Nipples do NOT mean it's a Female!​

Males and females both have two nipples each. Do not use nipples or nipple size as an indication of gender. Men have nipples, too. Same idea. Don't go by nipple size either. It's all about the genitalia.

Just found surprise babies? Surprise again!​

This is such a common occurrence and the news just gets worse. If you had to have those pet store pigs, now you are finding out exactly why we advise against it. If you ended up with a fertile male and female and your female gave birth while the male was still in the cage, guess what? She could very likely be pregnant again! Why? Because about an hour or so after giving birth, a female goes into heat again in a big way! So, now a second, back-to-back (not so healthy) and usually larger-litter pregnancy is quite possible and any decisions you try to make with the current increase in population needs another 45 days of waiting to see if she is pregnant again. Her body has already been depleted of nutrients, particularly calcium and related minerals, so back-to-back pregnancies are riskier for Mom and babies. And if she is pregnant, you'll have to wait another 10 weeks to find out how many of what gender guinea pigs you'll have in total.

How to SEX Guinea Pigs​

Females (or sows)​

The sows usually have a smooth swelling over their genital area. Sometimes, it can be bumpy looking, making you think it might be a male! If you gently part the genital opening, on a sow, a ""Y"" shaped opening should appear.

Males (or boars)​

Press gently just above the genital area. If it's a male, you should be able to make the penis slowly and gently protrude to confirm. Don't be fooled by appearances. Sometimes, it doesn't look like there is a penis there at all -- especially in heavier, older males -- the penis can be tucked away in folds of skin, looking a lot like a female! You should try to get the penis to protrude. If it is a male, you can usually feel the inner part of the shaft (just under the skin) in the same area -- above the genitals -- by very gently touching and moving your finger over that area. You can feel the ridge just above the penis.

Also, if there is a pucker or protrusion of skin at the top of the genital area, then that is a good indication that there is a penis tucked away underneath. But, be sure to get it to extrude to confirm it.

Young males don't have pronounced testicles, but have a raised donut shape around their rectum area. Testicles should be pretty obvious on grown, adult males (but not always).

From Newborns to Neutered Males​

It seems easy when you are looking at clear pictures designed to highlight the differences. It can be a little tougher in practice. The following images highlight males and females at a variety of ages to help give you additional visual references.

Images coming soon.

Accidental Pregnancy​

Have a good vet lined up ahead of time for any last minute complications. Remove the male, if you still have them together. She could deliver or miscarry at any time and you do not want her getting pregnant again. She can stay with any other adult females or a neutered male, even after delivery.

Gestation time for guinea pigs is about 59-73 days, or a little over two months. You won't be able to tell for sure until about 40+ days. It's a good idea to weigh her regularly to chart and track the weight gain.

Babies, when to separate​

Boars MUST be separated from their mother at 3 to 4 weeks -- 3 weeks if they are normal and healthy, 4 weeks if they need an extra health boost and are showing no signs of mounting behavior. Never leave a boar with his mother or sisters longer than 4 weeks.

Females and Heat​

The vagina is normally closed by a membrane (hymen) except during estrus (heat) and at parturition (birthing). It actually dissolves (becomes mucousy) when they go in heat and will reseal itself afterwards. Sows come 'into cycle' every 15-17 days for 24 to 48 hours.

For females, in addition to being optimally fertile when in heat, their behavior can be a bit 'hormonal.' They can be bossy to other pigs in the cage during that time and display mounting and aggressive behavior as well. It is totally normal. They do not menstruate. They do not bleed when 'having their period.' If you ever see bloody discharge, look to the urine as the culprit -- usually a sign of a Urinary Track Infection (UTI) or some version of stones (kidney, bladder, etc.) or possibly cysts. Presence of blood should always be taken seriously -- typically requiring a vet visit. Those kinds of problems can be difficult to diagnose and treat, and the sooner the better as well.

Males will be Males​

Male guinea pig ejaculate turns into an incredibly solid, hard white opaque looking substance. It's why we all refer to it as ""Boar Glue."" It rivals super glue in strength! It's almost impossible to get it out of fabric or other guinea pigs' hair (you pretty much have to cut it out). When a male impregnates a female, that characteristic creates a strong plug in the female, sealing that area giving his sperm maximum chance to take hold.

Whether you have two fertile males living together or a neutered male living with a female, you'll typically find some strange rubbery and later hard clumps of boar glue. It's normal.

Genital Hygiene for Males​

If you have one or more male guinea pigs, you should be checking their genital area regularly (about every other week or so). Extrude the penis and make sure it looks clean and healthy. Sometimes a strand of hay or hair will get caught and cause problems. Or it can get gunked up. Infections can result. Clean it gently with warm water if necessary. Also, check the anal area to make sure there is no sign of blockage or impaction.
Next article in the series 'Getting Started with Guinea Pigs': HAY for HAPPY piggies
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