Rat Reproduction - Anatomy & Physiology

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BACK TO REPRODUCTIVE SYSTEM
BACK TO SMALL DOMESTIC MAMMALS


Male

Penis

  • Penis is easily extruded from the prepuce.
  • Os penis lies within the tissue of the penis.

Testes

  • Two testes in an external scrotum.
  • Testes descend between day 30-40.
  • Open inguinal canals throughout life.
    • Allows the testes to shrink and return to the abdomen during the non-breeding season.
  • Head and tail of the epididymis are the sites of extremely large fat pads.

Puberty and Sexual Maturity

  • Sexually mature at 6-8 weeks


Mammary Gland

  • Teats are absent.

Female

Reproductive tract


Oestrous Cyclicity

  • Non-seasonal polyoestrus
  • Oestrus cycle 4-5 days.
  • Duration of oestrus is ~14 hours.


Copulation

  • Evidence that mating has occured is the 'copulatory plug'
    • Forms in the vagina.


Gestation and Offspring

  • Gestation length is 20-22 days.
  • Litter size 6-16
  • Altricial young
    • Eyes open at 12-14 days.
  • Earliest weaning age 21 days.
  • Care not to stress mother or she may cannibalise the young.


Mammary Gland

  • 5 pairs of teats.