General Care
I currently keep a core colony of about 35-40 adults in a 50gal wide aquarium and provide them with branches and ornamental 'ruins' to climb on, a bunch of hideaways and 2 small wheels to keep themselves busy. The bedding I use is aspen, which is low on dust on easy on the respiratory tract, which is very important as they are very sensitive.
The dietary needs of pygmy mice are different from the average mouse. I feed them a premium quality finch and canary seed mix, with added parakeet treat mix which has small bits of dried fruits and vegetables. Proportionate to their body size, they eat quite a lot as they have very high metabolisms. I've found that they rarely touch any fresh vegetables or fruit that are offered but mine have accepted minced carrot now and then.
Breeding
Healthy pups start with healthy parents, which is why it is so important to make sure that breeding animals are maintained in top condition through proper diet and care. Despite their small size, pygmy mice prefer a larger enclosure for breeding, as well as warmer temperatures. They do well in either a pair or colony setting. In a colony the females usually give birth in one place and take care of each other's young. Although it is difficult to prevent inbreeding altogether in a colony setting, I started out with a diverse genetic background and with some care it is possible to keep it to a minimum. Every now and then I do trades for new bloodlines to keep my colony strong and healthy.
Raising the Young
It is best not to disturb a pygmy mouse nest as much as possible. The pups develop rather quickly. They are fully furred and have their eyes open between 12-14 days old and full weaning taking place at only 21-26 days old. The pups have a grayish coat which they molt at 2-3 months old, which is replaced by the reddish brown adult coat. In this time it is normal for them to look a little 'scruffy.' In the picture above is an adolescent male beginning his molt. He is full grown at this point as well, and the hand helps show the proportionate size of these mice.
