Reproductive Characteristics Reference Table for Small Mammals - Anatomy & Physiology

Species	Rabbit	Chinchilla	Chipmunk	Gerbil	Guinea Pig	Golden Hamster	Mouse	Rat
Reproductive Pattern	No True Oestrous Cycle	Seasonally Polyoestrous:Breeds November-March	Seasonally Polyoestrous:Breeds March-September	Polyoestrous	Polyoestrous	Polyoestrous	Polyoestrous	Polyoestrous
Length of Oestous Cycle	Every 4 days	30-35 days	14 days	4-6 days	15-16 days	Every 4 days	4-5 days	4-5 days
Type of Ovulation	Induced:Occurs Within 10 hours of Mating	Spontaneous	Spontaneous	Spontaneous	Spontaneous	Spontaneous	Spontaneous	Spontaneous
Gestation Period	28-32 days	111 days	28-32 days	24-26 days	63 days	15-18 days	19-21 days	20-22 days
Average Litter Size	2-7	2-3	2-6	3-6	2-6	3-7	6-12	6-12
Type of Young at Birth	Altricial	Precocial	Altricial	Altricial	Precocial	Altricial	Altricial	Altricial
Weaning Age	4-6 weeks	6-8 weeks	6-7 weeks	3-4 weeks	3-4 weeks	3-4 weeks	18 days	3 weeks
Age of Sexual Maturity	5-8 months	8 months	12 months	10-12 weeks	6-10 weeks	6-10 weeks	3-4 weeks	5-6 weeks

Key Words

Altricial: newly born young are relatively immobile, have closed eyes, lack hair, and must be cared for by the adults. Altricial young are born helpless and require care for a comparatively long time.
Precocial: young have open eyes, have hair, large brains and are immediately mobile and somewhat able to defend themselves against predators.