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− | <big><center>[[Reproductive System|'''BACK TO REPRODUCTIVE SYSTEM''']]</center></big>
| + | == MALE == |
| | | |
− | <big><center>[[Reproductive_System#Small_Domestic_Mammals|'''BACK TO SMALL DOMESTIC MAMMALS''']]</center></big>
| + | === 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 [[Erection - Anatomy & Physiology|erect]]. |
| + | * 1.5cm in length |
| + | * '''Sigmoid flexure''' |
| + | * '''Os penis''' in the distal portion. |
| + | ** The small supporting bone is known as the '''baculum'''. |
| + | |
| + | |
| + | === Copulation === |
| + | |
| + | * [[Spermatogenesis_and_Spermiation_- Anatomy & Physiology|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 === |
| + | |
| + | * [[Ovary - Anatomy & Physiology|Ovaries]] are just caudolateral to the [[Renal Anatomy - Anatomy & Physiology#Common Anatomy|kidneys]]. |
| + | * [[Uterus - Anatomy & Physiology#Anatomical_Types_of_Uteri|Bicornuate duplex uterus]]. |
| + | * [[Uterus - Anatomy & Physiology|Uterine lumena]] do not fuse. |
| + | ** The two uterine horns continue into seperate [[Cervix - Anatomy & Physiology|cervices]] |
| + | ** Open separately into a single [[Vagina and Vestibule - Anatomy & Physiology|vagina]]. |
| + | * Membrane covers [[Vagina and Vestibule - Anatomy & Physiology|vaginal]] opening except at oestrus and during [[Normal Parturition - Anatomy & Physiology|parturition]]. |
| + | |
| + | === 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 ==== |
| | | |
− | == Male ==
| + | * Long gestation period: 111 days. |
| | | |
− | * Thin-walled scrotal diverticula extend cranially on either side of the base of the penis. | + | ==== Litter ==== |
− | ** Only a very slight scrotal region is visible externally. | + | |
− | * Each diverticulum is occupied by the tail of the epididymis. | + | * Litter size 1-6 |
− | * Testes and head of the '''epididymis''' is in the region of the '''inguinal ring'''. | + | * Precocious offspring |
− | * Large fat body extends cranially into the abdominal cavity from the cranial pole of each testis.
| + | ** Weaning age is 6 weeks. |
− | * '''Vesicular glands''' are very long and tubular.
| + | |
− | * '''Prostate gland''' has paired large ventral lobes and paired small dorsal lobes.
| + | === Mammary Gland === |
− | * '''Bulbourethral glands''' are dorsolateral to '''ischiocavernosus muscles'''. | + | |
− | ** Isciocavernosus muscles are enormous, swelling on either side of the rectum and meeting over its top. | + | * Three pairs |
− | * Penis points caudally when relaxed and cranially when erect.
| + | ** One inguinal pair |
− | ** 5cm in length | + | ** Two lateral thoracic |
− | ** Sigmoid flexure | + | * Teats protrude sideways, allowing the young to sit beside the dam and suckle. |
− | ** Os penis in the distal portion.
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− | ----
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− | == Female ==
| + | [[Category:Small Mammal Reproduction]] |
| + | [[Category:Bullet Points]] |