page_title: Tasmanian devil
section_title: Reproduction
hierarchical_section_title: Tasmanian devil / Ecology and behaviour / Reproduction
caption_attribution_description: English: Created by User:Petaholes from data in Guiler, E.R., Observations on the Tasmanian Devil, Sarcophilus harrisii (Marsupialia&#160;: Dasyuridae) II. Reproduction, breeding and growth of pouch young, Australian Journal of Zoology, 1970, 18(1)63-70 he:קובץ:Tasmanina_Devil_development_heb.jpg
context_page_description: The Tasmanian devil is a carnivorous marsupial of the family Dasyuridae. It was once native to mainland Australia and is now found in the wild only on the island state of Tasmania.
  The size of a small dog, the Tasmanian devil became the largest carnivorous marsupial in the world following the extinction of the thylacine in 1936. It is related to quolls and distantly related to the thylacine. It is characterised by its stocky and muscular build, black fur, pungent odour, extremely loud and disturbing screech, keen sense of smell, and ferocity when feeding. The Tasmanian devil's large head and neck allow it to generate among the strongest bites per unit body mass of any extant predatory land mammal. It hunts prey and scavenges carrion as well as eating household products if humans are living nearby. Although devils are usually solitary, they sometimes eat together and defecate in a communal location. Unlike most other dasyurids, the devil thermoregulates effectively and is active during the middle of the day without overheating. Despite its rotund appearance, it is capable of surprising speed and endurance, and can climb trees and swim across rivers. Devils are not monogamous.
context_section_description: Females start to breed when they reach sexual maturity, typically in their second year. At this point, they become fertile once a year, producing multiple ova while in heat. As prey is most abundant in spring and early summer, the devil's reproductive cycle starts in March or April so that the end of the weaning period coincides with the maximisation of food supplies in the wild for the newly roaming young devils. Occurring in March, mating takes places in sheltered locations during both day and night. Males fight over females in the breeding season, and female devils will mate with the dominant male. Females can ovulate up to three times in a 21-day period, and copulation can take five days; one instance of a couple being in the mating den for eight days has been recorded. Devils are not monogamous, and females will mate with several males if not guarded after mating; males also reproduce with several females during a season. Females have been shown to be selective in an attempt to ensure the best genetic offspring, for example, fighting off the advances of smaller males. Males often keep their mates in custody in the den, or take them along if they need to drink, lest they engage in infidelity. Males can produce up to 16 offspring over their lifetime, while females average four mating seasons and 12 offspring. Theoretically this means that a devil population can double on an annual basis and make the species insulated against high mortality. The pregnancy rate is high; 80% of two-year-old females were observed with newborns in their pouches during the mating season. More recent studies of breeding place the mating season between February and June, as opposed to between February and March.
  Gestation lasts 21 days, and devils give birth to 20–30 young standing up, each weighing approximately 0.18–0.24 grams (0.0063–0.0085 oz). At birth, the front limb has well-developed digits with claws; unlike many marsupials, the claws of baby devils are not deciduous. As with most other marsupials, the forelimb is longer (0.26–0.43 cm or 0.10–0.17 in) than the rear limb (0.20–0.28 cm or 0.079–0.110 in), the eyes are spots, and the body is pink. There are no external ears or openings. Unusually, the gender can be determined at birth, with an external scrotum present.
  Tasmanian devil young are variously called "pups", "joeys", or "imps". When the young are born, competition is fierce as they move from the vagina in a sticky flow of mucus to the pouch. Once inside the pouch, they each remain attached to a nipple for the next 100 days. The female Tasmanian devil's pouch, like that of the wombat, opens to the rear, so it is physically difficult for the female to interact with young inside the pouch. Despite the large litter at birth, the female has only four nipples, so there are never more than four babies nursing in the pouch, and the older a female devil gets, the smaller her litters will become. Once the young have made contact with the nipple, it expands, resulting in the oversized nipple being firmly clamped inside the newborn and ensuring that the newborn does not fall out of the pouch. On average, more females survive than males, and up to 60% of young do not survive to maturity.
  Milk replacements are often used for devils that have been bred in captivity, for orphaned devils or young who are born to diseased mothers.  Little is known about the composition of the devil's milk compared to other marsupials.
  Inside the pouch, the nourished young develop quickly. In the second week, the rhinarium becomes distinctive and heavily pigmented. At 15 days, the external parts of the ear are visible, although these are attached to the head and do not open out until the devil is around 10 weeks old. The ear begins blackening after around 40 days, when it is less than 1 cm (0.39 in) long, and by the time the ear becomes erect, it is between 1.2 and 1.6 cm (0.47 and 0.63 in). Eyelids are apparent at 16 days, whiskers at 17 days, and the lips at 20 days. The devils can make squeaking noises after eight weeks, and after around 10–11 weeks, the lip
caption: Developmental steps in the maturation of Tasmanian devil young. The diagonal lines indicate the amount of time the changes take; for example, it takes about 90 days for a devil to develop fur over all its body.
exif: {}