What does a dog’s reproductive system look like?
Expert Answer
A female dog’s reproductive organs consist of the ovaries, oviducts, uterus, vagina and vulva. Her ovaries sit on the underside of the third or fourth lumbar vertebra and produce eggs and estrogen. The oviducts are 5 to 8 cm tubes that carry and fertilize the eggs. The uterus is bicornuate (two-horned), with fetuses developing in the horns; because the horns are well developed, a female can deliver a litter of a dozen or more puppies. Her vagina is long with strong circular muscle, and the vulva is the external organ made up of the lips and clitoris.
A male dog’s reproductive organs consist of the testes, sperm ducts, accessory glands and penis. The testes are small, oval, one on each side, and produce sperm and testosterone. During the mating season a male’s testes become enlarged and elastic.