section_path: Anatomy/Reproductive system/Males
section_name: Males
paragraph_text: Males
  
  Most male marsupials, except for macropods and marsupial moles, have a bifurcated penis, separated into two columns, so that the penis has two ends corresponding to the females' two vaginas. The penis is used only during copulation, and is separate from the urinary tract. It curves forward when erect, and when not erect, it is retracted into the body in an S-shaped curve. Neither marsupials nor monotremes possess a baculum. The shape of the glans penis varies among marsupial species.
  
  The shape of the urethral grooves of the males' genitalia is used to distinguish between Monodelphis brevicaudata, M. domestica, and M. americana. The grooves form two channels that form the ventral and dorsal folds of the erectile tissue. Several species of dasyurid marsupials can also be distinguished by their penis morphology. Marsupials' only accessory sex glands are the prostate and bulbourethral glands. Male marsupials have one to three pairs of bulbourethral glands. Ampullae of vas deferens, seminal vesicles or coagulating glands are not present. The prostate is proportionally larger in marsupials than in placentals. During the breeding season, the male tammar wallaby 's prostate and bulbourethral gland enlarge. However, the weight of the testes does not vary seasonally.