Reproductive Development in the Female Golden Hamster in Relation to Spontaneous Estrus

Abstract

Pubertal maturation of the reproductive-sexual behavior system in 22 female hamsters was studied with primary orientation toward the manifestation of estrus. Spontaneous estrus was demonstrated as early as 26 days of age, vaginal opening was seen by 5-10 days, and ovulation occurred as early as Day 29. Dependable coordination between estrus, ovulation, and other reproductive factors necessary for successful pregnancy was not consistently seen, however, until 35 days of age. Prior to this age, anovulatory estrus, anestral ovulation, and nonproductive fertile matings may be seen. While the hamster is thus revealed as a species capable of extremely early and rapid sexual development, during development a period of adolescent sterility of approximately 9 days exists during which time coordination of the many-faceted features of reproduction occurs.