Type of estrus: polyestrous (heat at fairly regular times- year round)
Frequency of estrus: Every 4-5 days
Length of estrus: Usually 12 hours (most often at night)
Return of estrus after delivery: 12-24 hours
Female menopause (estropause): 18 months (variable, but most common 15-18 months)
Pelvic fusing in females: No
Number of teats on a female: 12
Number of uteruses: 2 (“uterine horns”)
Pregnancy and Babies
Gestation: 21-23 days
Weaning age: 21-28 days
Average litter size: 6-12 (variable from 1-22)
Average size of newborn: 6-7 grams
Fur on babies: 7-10 days
Eyes open: 12-15 days
Ear canal open: 12-14 days
Descent of testes: 15-50 days
The Rat Guide and its affiliates accept no responsibility for misuse or misunderstanding of its information. This guide in whole or part, exists solely for the purpose of recognizing and understanding the care and illnesses in the pet rat. Please seek advice and treatment from a qualified Veterinarian if your rat is ill.
2000 - 2023 by Karen Grant RN. All rights reserved.
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