Breeding Right for You
This is a tough question to ask, but its the first question any breeder must ask themselves. Is this a good idea or not. If you have major life events on the horizon those should be taken into consideration. Breeding gerbils is a slippery slope, one that you will soon find yourself surrounded by several dozen gerbils. They will need cages, food, bedding, waters, toys, and enrichment. Each day you will need to care for your gerbils and cleaning tanks can be a several hour job. Breeding gerbils also has a huge emotional toll. With life comes death. Gerbils do not live very long and its not surprising that most breeders only last two the three years.
Selecting a Breeding Pair
Gerbils breed best in pairs with one male and one female. Sometimes gerbils will breed in groups, but this is not recommended. Two males will fight over who gets to breed with the girl. Two girls will fight over the pups, and this can often lead to pup starvation and death. Will gerbils breed in mix sexed groups, absolutely, but there is often fighting and death if done this way. A responsible breeder would choose to breed in pairs, every single time.
Males and females can become sexually active as young as five weeks, but they aren't mature or full grown till much later. Gerbils are generally mature enough for breeding around 4 months. Females should be full grown by four months, most breeders choose females that are between four months and a year old for their first litter. Older females may have difficulties conceiving and birthing pups. Many females lose the ability to become pregnant in their old age (30+ months). Males may take up to a year to reach their full size. For this reason, breeders often choose to breed males that are full grown and over a year old. Males are generally always able to procreate even in their old age, however they might be slower to breed.
Breeders should have goals and plans. They should have a solid understanding of genetics and gerbil colors. Understanding these topics will help you choose which gerbils to breed with each other to get the desired results.
Introductions and Mating Behaviors
Once you've chosen your male and female you should set up a split cage. Typically females will go into to estrus (head) approximately two days after being introduced to a male. Females will then go in to heat every three to four days until they are pregnant. Females generally go into heat in the late afternoon or evening.
Females signal their willingness to mate by running up to the male gerbil and promptly turning around. She may then run forward and posture herself by arching her back slightly and flexing her hips. Females may thump, its usually a softer and more rapid thumping then the alert. You may notice a female flex her back, causing a kind of ripple along her back. A truly desperate female might go so far as to try and scent mark, hump, or even pee on the male who is ignoring her advances.
Males for the most part are always ready to breed. They will often try to breeding with females who are not in heat. They also thump their feet in a soft and rapid call.
During copulation gerbils will often check their genitals and clean themselves as they go.
Gestation and Birth
Gestation takes about twenty four days. During this time your female will start to put on weight, monitoring her weight is one of the easiest ways to tell if she is pregnant. Around the twelfth day you may begin to notice her lower abdomen change shape and her belly may feel thicker. Around the eighteenth day she will start to look very pregnant, you may be able to see the pups wiggling around inside. As she gets closer to giving birth she may build elaborate nests. You should take the opportunity to clean the cage about two days before she gives birth. As she nears the end of her pregnancy she may evict the male from the nest and force him to sleep alone. You may notice her stretching more. If you do not want your female to have another litter, it is important to remove the male before she gives birth. Males make excellent fathers and their presence does help the pups grow. Males help keep the pups warm and relieve the mother so she can take care of herself. It is recommended that females have help raising litters either from their mate or from a female pup from one of their previous litter.
Most gerbils give birth in the early hours of the morning. During labor gerbils will stretch to help move the pup. They will also pull the pup out once the head emerges. Generally speaking gerbils can deliver their pups without any sort of assistance. Pups are born with their eyes and ears closed. They start to grow fur around day seven. Their eyes start to open on day seventeen. Pups are considered weened by 35 days. Read more about Pup Development.
During a females first litter, it is not uncommon for pups to be a little bruised from birth. They may even have bite marks on their nose and face. These will heal up, but the bite marks are known to scar and cause white hairs to grown in.
During birth and after gerbils will immediately mate again and if successful she will be pregnant again. The size of her current litter will affect the length of time it takes the second litter to be born.
It does happen that mothers will evict their pups at weaning time by chasing and attacking them. Remove all the pups immediately. It is best to not breed her again or her offspring.
In general females should only have two to three consecutive litters, at which point she will need to be retired and given time to recuperate for several months. Many breeders will retire breeding pairs when the litter is about four to five weeks old before the next one is born by taking the all the males out and moving them into their own cage.
When separating your gerbils by sex be sure to give consideration to your future plans. Its is often best to keep the mother and two or three of her daughters if you plan to re-breed the mom or any of the daughter in the future. The same goes for the males.