Chipmunk Reproduction - Anatomy & Physiology

Male

Penis

• Os penis lies within the tissue of the penis.

Testes

• Two testes in an external scrotum.
• Testes descend into the scrotum at the beginning of the mating season (January) and begin spermatogenesis.
• Open inguinal canals throughout life.
  • Allows testes to shrink and return to the abdomen in the non-breeding season.

Puberty and Sexual Maturity

• Sexually mature at 6-7 weeks.

Mammary Gland

• Teats are absent.

Female

Reproductive Tract

• Bicornate uterus
  • Short uterine body
  • Single cervix

Puberty and Sexual Maturity

• Sexually mature at 12 months.

Oestrous Cyclicity

• Seasonally Polyoestrous.
• Spontaneous ovulator.
• Breeding season is March-September.
• Length of oestrous cycle: 14 days
• Oestrus lasts three days.
• Advertises willingness to mate with persistent chipping noise on the second day of oestrus.

Gestation and Offspring

Gestation

• Gestation period 28-32 days.

Litter

• Litter size 2-6
• Altricial young
  • Weaned at 6-7 weeks

Mammary Gland

• 4 pairs of teats.