1. Pups are born blind, deaf, and hairless.

2. Skin pigment develops at 3 days.

3. Ears develops at day 4.

4. Hair begins to develop at day 5.

5. Fully haired at day 7.

6. Ears open at day 9-10.

7. Eyes opens at day 12-14. 

8. Wean at approximately 21 days. 

Reproductive Biology

1. Six weeks to sexual maturity

2. 4-5 day estrus cycle

3. 19-21 day gestation peroid

4. Average litter size 6-8 pups

5. Wean at 21-28 days of age

6. Reproductive lifespan variable

Males

1. Start breeding at 8 weeks

2. Up to one year as breeders or studs

3. Retire at one year        some strains (C57BL/6) fertility decreases at 10 months

4. Retire if infertile with young females

5. Rotational vs. same cage stable matings

   
   

Females

1. Start breeding at 7-8 weeks

2. Expect 2-8 litters

3. Retire at 6 months after set-up

4. Retire when litter size drops

5. Retire if no litters in two months

6. Hold for two weeks after retirement