Chinchilla Reproduction - Anatomy & Physiology

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MALE

Scrotum and Testes

  • Only a very slight scrotal region is visible externally (no true scrotum).
  • Thin-walled scrotal diverticula extend cranially on either side of the base of the penis.
  • Each diverticulum is occupied by the tail of the epididymis.
  • On either side of the anus are two postanal sacs.
    • Caudal epididymis can lie in the postanal sacs.
  • Testes and head of the epididymis is in the region of the inguinal ring.
  • Large fat body extends cranially into the abdominal cavity from the cranial pole of each testis.


Accessory Sex Glands

Vesicular Glands

  • Very long and tubular.

Prostate Gland

  • Paired large ventral lobes and paired small dorsal lobes.

Bulbourethral Glands

  • Dorsolateral to ischiocavernosus muscles.
    • Ischiocavernosus muscles are enormous, swelling on either side of the rectum and meeting over its top.

Penis

  • Penis points caudally when relaxed and cranially when erect.
  • 1.5cm in length
  • Sigmoid flexure
  • Os penis in the distal portion.
    • The small supporting bone is known as the baculum.


Copulation

  • Spermatogenesis occurs at about 2-3 months.
  • Copulatory maturity is not until about 8 months.
  • Breeds all year round.
  • Copulatory plug at mating.

FEMALE

Reproductive Tract

Puberty and Sexual Maturity

  • Puberty at ~8 months
    • Puberty can be same year as birth, but if the chinchilla is born late in the year it will not reach puberty until the next breading season.


Oestrous Cyclicity

  • In the Northern Hemisphere the breeding season is November-May.
  • Seasonally polyoestrus with a mean cycle of ~40 days.
  • Post-partum oestrus.
    • Often two litters per year, three are possible.
  • Breeding life is ~10 years.


Gestation and Offspring

Gestation

Litter

  • Litter size 1-6
  • Precocious offspring
    • Weaning age is 6 weeks.

Mammary Gland

  • Three pairs
    • One inguinal pair
    • Two lateral thoracic
  • Teats protrude sideways, allowing the young to sit beside the dam and suckle.