Author: Jamie Huggins
of Huggable Pets- Chinchillas
Chinchilla Pregnancy 101
When breeding chinchillas its important to understand how chinchilla reproduction works and just what is happening during pregnancy. The information in this article is meant as a guideline to give a general idea about chinchilla reproduction. Not every chinchilla will follow the same heat cycles or the same duration of pregnancy.
Let’s start with the process of mating. The estrus cycle of a chinchilla is about 28 days and the heat period is 2 days so chinchillas are capable of getting pregnant every month but the likelihood of mating seems to be better during the late winter/early spring months. As the days start to get longer the chinchillas are most likely to breed. Also during the late summer/early fall months chinchilla breeding will slow down. Even in a controlled environment they seem to sense the light change and will breed accordingly.
Once a pair is bonded it can take anywhere from several weeks to over a year for them to successfully mate. Some signs that a mating has taken place would be tufts of hair in the cage and/or finding a breeding plug.

Breeding Plug. Taken by Christi, a club member
Pregnancy on a chinchilla can be hard to detect especially during the first 3 months. If your chinchilla is not used to being handled its best to leave her alone if you suspect she is pregnant. Stress can cause her to abort the babies. If your female is used to your affection and seems to want to continue to be outside of the cage it is alright to hold her. Just be sure to use extra care. Many chinchillas will go through mood swings during pregnancy. Some of my usually friendly females will begin spraying urine at me when they are pregnant. Other females that shy away from my hand will become more affectionate during those 111 days. Pay attention to your animal’s wishes and honor them.
After the 90 day mark you may notice your female’s nipples getting redder and longer. She has six nipples, three or each side. You can locate them by placing your hand under her “armpit” and running it down her belly in a straight line. Before pregnancy and during the first months the nipples will be small “bumps” and very hard to locate. By delivery they will be almost as long as her hair. You will also notice that she is gaining weight and her belly is rounder and firmer. First time mothers usually have smaller babies and many times have single births. These can be harder to detect. Chinchillas carrying multiple kits will be obviously large. As the female gets closer to her delivery date you may be able to see the babies move.
Now let’s look at the development of a chinchilla during the 111 days of pregnancy. The information and pictures below are based on an article written by H.H. Greenlee, D.V.M.
 At 30 days it weights .1 gram |
 At 45 days it weights 1 gram |
 At 60 days it weights 10 grams |
 At 80 days it weights 25 grams |
 At 100 days it weights 40 grams |
 At 111 days it weights 45 grams |
Finally we arrive at the day of delivery. The average length of pregnancy is 111 days however some
chinchillas will deliver early and others will go a bit later. The majority of chinchillas will
birth their babies during the early morning hours but they can deliver any time of day. Birth
is a very natural thing and your female should be able to handle everything on her own. When
she is in active labor you may notice her huddled up in an awkward position. She may bend down to
check the process from time to time as she begins pushing the baby out. Once the baby is delivered,
she will clean it a little and may sit on it to let it nurse. If she is giving birth to multiple babies she will go back into labor again. It’s not uncommon for babies to come as much as 45 minutes apart. When the mother is delivering the next kit, the first of the litter is left alone and wet so it is important that the room be a comfortable temperature with no cool drafts.
Once all of the babies are delivered the mother should tuck the babies under her and keep them warm as they dry. She will have delivered an afterbirth, (the placenta that held the baby) for each baby she delivered which should be removed from the cage. Many chinchillas will nibble at the afterbirth, which is rich in protein, but they should not be permitted to eat the entire thing. Chinchillas are vegetarians and therefore can not digest meat. Eating too much of the placenta will cause impaction and other digestive problems.
It’s important to know that the female will go back in heat after delivery and will mate with a male sometime within the next 72 hours if he is not removed from the cage. I prefer not to let my females breed again right after delivery; however this is a common practice for many breeders. During this next mating, newborn kits can easily be trampled and killed. If you choose let them breed again right away, it is important to place a small can or box in the cage where the babies can hide and be safe. Before allowing this breed-back it’s important to remember what is going on during pregnancy. With a new litter of chinchillas, the female is providing lots of milk which requires minerals, fats, and proteins to be pulled from her body. If she is pregnant again she also has to supply nutrients to the growing embryo. Looking back at the growth chart above you will notice a gradual growth up until about the 60th day and then rapid growth begins. The drain on the mother during the rest of her pregnancy is intense. There is a lot going on inside her as the babies bones begin to harden, hair begins to grow, and muscles are strengthening. If the mother is still nursing kits during this point in her pregnancy she may become run down as her body works to provide for the needs of all of her kits. For this reason it is best to wean her kits at 6 weeks to give her body the ability to provide everything the new babies need to be born healthy. Once the next litter is born she should be given a long resting period with no matings to give her body time to recover.
I hope you have found this crash course in chinchilla reproduction helpful. Keep in mind that each chinchilla is different and not every mating and pregnancy will go just as described above.
Resources:
King Chinchilla Manual
authors Jay Thompson & Kathleen B. Mihalcik.
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