Hamster Reproduction - Anatomy & Physiology

()Map REPRODUCTIVE SYSTEM (Map) SMALL DOMESTIC MAMMALS

Male

The anogenital distance is longer in the male, which has a more prominent genital papilla.

Penis

• Os penis lies within the tissue of the penis.
  • Supporting bone is the Baculum.
    • Baculum consists of two lateral prongs and a dorsal prong.

Testes

• Two large testes in an external scrotum.
  • Retained in the scrotum by a pad of fat in the inguinal canal.
• Chinese Hamster:
  • Testes remain internal.

Accessory Sex Glands

• Several large accessory glands including:
  • Ampulla Glands
  • Seminal Vesicles
  • Coagulating Glands
  • Prostate (three-lobed)
  • Bulbourethral Glands
• Produce a urethral plug.

• Scent gland on each flank to mark territory.

Mammary Gland

• Teats are absent.

Female

Reproductive Tract

Ovary

• Ovaries are oval in shape, situated dorsolateral to the kidneys.
  • Completely enclosed in a fat-filled ovarian bursa.
  • Uterine artery provides a major blood supply to the ovary.
  • Coils of the ovarian and uterine arteries anastoamose close to the ovary.

Oviduct

• Oviduct is long and tighly coiled.

Uterus

• Duplex Uterus
  • Two seperate cervices.
  • Uterine horns remain divided until uniting in a single vagina.

Vagina

• The urinary opening is cranial and the anus is caudal with the vaginal opening in between.
• Vagina has a pair of vaginal pouches.
  • Extend caudally, terminating at the level of the vaginal orifice.

Oestrous Cyclicity

• Spontaneous ovulator.
  • Ovulation occurs ~ 12 hours after the LH surge, usually resulting in the release of ova at night (hamsters are nocturnal).
• Seasonally polyoestrus
• Oestrus every 5-7 days
  • Secretes copious white vaginal discharge during oestrus.
    • Changes consistency from stringy to waxy over the 3 day oestrus period.
• Post-partum oestrus

Copulation

• Lasts 30 minutes.
• Mating may be confirmed by the presence of a 'copulatory plug'.
  • A creamy, gelatinous plug formed from secretions of the male accessory glands.
• Pseudopregnancy can occur after an infertile mating.

Mammary Gland

• 6 pairs of teats
• Extend from the thoracic to inguinal region.

Breed Differences

Syrian (Golden) hamster

Syrian Hamster Foetus during Late Gestation- Courtesy of Andrew Crook, Copyright RVC 2008

• Sexually mature at 6-8 weeks
• Gestation period: 6-8 days
• Litter size 5-9: offspring
  • Weaned at 21-28 days.

Russian Hamster

• Sexually mature at 6-8 weeks
• Gestation period: 6-8 days
• Litter size: 4 offspring
  • Will cannabilise young if disturbed.
  • Weaned at 16-18 days.

Chinese Hamster

• Sexually mature at 7-14 weeks
• Gestation period 7-14 days
• Litter size: 4 offspring
  • Will cannabilise young if disturbed.
  • Weaned at 21 days.