No matter what color the chins are, a male and female cannot be housed together without a getting-accuainted period. The couple-to-be should be put in separate cages side by side so they can communicate with and "sniff at" each other. Even though we can't smell a chinchilla, each has a scent that is identifiable by other chins, and mates need to become familiar with it before being put in the same cage. Allow at least one week for an introduction jperiod. Then, when putting the male in the female's cage, plan to watch their activities carefully. FAILURE TO DO SO COULD RESULT IN SERIOUS INJURIES OR EVEN DEATH.
At first the male will probably be more interested in the cage than in his prospective mate, and it's quiet comon for him to check out all four corners and even gnaw away on chew blocks before acknowledging her. She, on the other hand, will be very interested in the intruder and will follow him around the cage. Once he's checked out the cage, a little rough-housing may take place as the two take turns chasing each other around. They may pause from time to time to chew on each other's ears and nibble the fur around their mate's eyes as they try to decide whether the prospective spouse is suitable. The chewing may look rough, but unless it turns to blood-letting biting the animals seem to enjoy it. If the male or the female becomes overly aggressive and nibbling turns to attacking or "hacking away" at the other chin so that the fur literally flies, separate them immediately.
When the female does the rejecting, she usually doesn't use her teeth, at least not at first. She will instead aim her clitoris and shoot urine at the intruder. (She can do this to humans, too, aiming for the eyes.) As soon as the female puts her back into the corner and rears up on her hind legs to give the male a shower, it's time to separate them as well.
Another week of being side by side should lessen the fear and hostility expressed by the animals. Chins seldom reject a prospective mate completely, but if it does happen there is no choice but to replace one of them, preferably the more aggressive animal. Once acceptance has been achieved, there is seldom a serious hassle between the two until the female comes into heat and we personally agree on this. That's how our Bei and GumGum got mated together
A female chinchilla is able to breed at approximately seven to eight months of age. She will come into cycle about every 30 to 40 days, but this doesn't mean that she's always willing to breed then. In fact, until chinchillas feel secure in their surroundings, they will not reproduce.
An alert chin owner can tell when the female is approaching her most receptive period. The male will become much more attentive, sniffing, and nuzzling, sometimes wagging his tail, and even vocally communicating his desire to mate. Shortly before the female is ready to breed, a small whitish, waxlike mating plug will be ejected from the vagina. Sometimes the plug is visible in the cage; more often than not, it is mixed in with the litter or eaten by one of the animals. As her mating time approaches, the male will become more aggressive and some roughness might occur simply because the male is ready long before the female will accept him. While some males are willing to bide their time, others become very aggressive and may have to be removed for a few hours or even a day until the female is more willing. If a large juice can is used in the cage as a hide-away and a toy, remove it when you see mating attempts or the female may choose to hide inside it until her conception period id over.
When a breeding attempt has taken place, the male will emit a cry best described as a hiccuping sound. He will also emit a wax-like substance during copulation that will harden to temporarily retain the semen in the vagina. After a breeding attempt has taken place, check the male to make sure he is able to withdraw his penis back into the protective foreskin. Occasionally an inexperienced male develops a "hair ring" around his penis during copulation and is unable to remove the hair himself. Remove it if necessary. Unless redness and swelling occur (signs of infection and the need for medication), nothing more need to be done.
The male and female may remain in the same cage until the babies arrive.