page_title: Tammar wallaby
section_title: Breeding and development
hierarchical_section_title: Tammar wallaby / Ecology and life history / Breeding and development
caption_attribution_description: Macropus eugenii in Budapest Zoo
context_page_description: The tammar wallaby, also known as the dama wallaby or darma wallaby, is a small macropod native to South and Western Australia. Though its geographical range has been severely reduced since European colonization, the tammar remains common within its reduced range and is listed as "Least Concern" by the International Union for Conservation of Nature. It has been introduced to New Zealand and reintroduced to some areas of Australia where it had been previously eradicated. Skull differences distinguish tammars from Western Australia, Kangaroo Island, and mainland South Australia, making them distinct population groups or possibly different subspecies.
  The tammar is among the smallest of the wallabies in the genus Macropus. Its coat color is largely grey. The tammar has several notable adaptations, including the ability to retain energy while hopping, color vision, and the ability to drink seawater. A nocturnal species, it spends nighttime in grassland habitat and daytime in shrubland. It is also very gregarious and has a seasonal, promiscuous mating pattern. A female tammar can nurse a joey in her pouch while keeping an embryo in her uterus.
context_section_description: The tammar wallaby has a promiscuous mating system. It is a seasonal breeder and births largely occur during late January and early February. During the breeding season, the male's prostate and bulbourethral gland enlarge. However, there does not appear to be any seasonal difference in the weight of the testes. Around two weeks before the first births, the males will begin sniffing the urogenital openings and pouches of the females to determine their reproductive status. After giving birth, females enter estrus and allow males to mate with them. However, a male that attempts to mate with an estrous female may face aggression from other males. A male can achieve reproductive success by mate-guarding. During the estrous period, males establish a dominance hierarchy and the higher ranking males will try to prevent subordinates from mating with estrous females. Several males may pursue a single female.
  The female tammar can conceive shortly after giving birth. Tammars undergo embryonic diapause and the blastocyst remains dormant for nearly a year. For the first half of the year, the presence of the joey in the pouch prevents the blastocyst from developing and experiments have shown that removing the joey within this first half will stimulate the blastocyst's development. However, after this, the blastocyst remains dormant even after the joey has left. It begins to develop by the summer solstice at the end of December and the female gives birth around one month later. After birth the newborn young climbs unaided by its mother from the birth canal to the pouch.
  When it reaches the pouch, the underdeveloped joey suckles the teat of one of the four mammary glands while the others recede. The joey remains attached to the teat for 100–125 days, after which it ceases its attachment but remains in the pouch and continues to suckle, but more intermittently. The joey begins to leave the pouch and eat grass at around 200 days when it is more developed. It still suckles, more forcefully but less regularly. By 250 days, the joey no longer needs the pouch, and it is fully weaned at around 300–350 days.  The tammar wallaby has been observed to engage in alloparental care, in which an adult may adopt another's young. Male tammars may live for around 11 years, while females live for 14 years.
caption: A female tammar wallaby with a joey in her pouch
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