Reproduction

Mating Behaviour

Tasmanian devils are marsupial mammals, meaning they have a pouch. However, devils differ slightly from other

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Photo sourced from: http://www.environmentafrica.org/

marsupials in that they are polyoestrous (having more than one oestrus period per year) and very foetal, meaning that during the mating season a female may mate with many males and is therefore capable of giving birth to many young, some of which may have been fathered by different males. More experienced males tend to have more success during copulation.

Females generally mate and produce their first litter of young towards the end of their second year/start of their third year. Females are capable of having young every year, until their 5th year, however most females will miss one year of breeding.

During the reproductive season females begin to develop a roll of fluid on the back of their neck, this fold is an important determinant of the success of breeding as the male uses it to drag the female to the den and to hold on during copulation. In the absence of this fold, the male may not be able to make the female submissive of him and consequently may not reproduce.  During oestrous, females also demonstrate a disinterest in food, nesting behaviours and lethargy. Male behaviour during the reproductive season, however, is characterised by an increase in energy and become more feisty when aware of the presence of a female in oestrous.

Oestrus Cycle

The oestrous cycle of the female usually begins between late February and early March and continues for 21 days. As females often mate with more than one male during any oestrous cycle, males often guard females for around 9 days after copulation in order to increase his chances of fathering a majority of that females offspring.

Mate Guarding

Once mated, males refuse to let females eat for the remainder of the mating period, which can last up to 2 weeks. Therefore, females must be in a very healthy condition, with a large supply of tail fat, prior to the mating season in order to reproduce. Furthermore, during guarding the male may be forced to fight with both males attempting to mate with the guarded female, as well as the guarded female herself, as she attempts to escape his guard. This often results in heavy scarring on both the face and rump of males.

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If a female doesn’t conceive young she will continue to return to oestrous and mate until she does fall pregnant. Gestation, once pregnant, is around 21 days, and the birthing process generally takes a few hours and occurs with the female standing.

Devil Young

Tasmanian devil young are referred to as either “pups”, “joeys” or “imps”

Between 20-40 (sometimes up to fifty) tiny, undeveloped young are born, however the mother may only raise a slideshow-3maximum of 4 young as she only has 4 teats in her backwards facing pouch. Once born the young must make their way into the pouch, by means of touch only, in order to start suckling on a teat. Once attached to a teat, it expands in the young’s mouth in order to prevent it from falling out of the pouch.

Despite being able to raise a maximum of 4 young, generally on 2-3 young survive and the rest of the young are eaten by the mother in order for her to regain nutrients lost during oestrous and pregnancy.

 

 

Photo Sourced from: https://500questions.wordpress.com/2012/12/01/39

Photo Sourced from: https://500questions.wordpress.com/2012/12/01/39

Development

When born devils are also about 1cm, approximately the size of a grain of rice. At the birthing stage young

devils only have a mouth, nose and developed front limbs and claws, allowing them to make their way to the pouch. Hind limbs are only buds at birth and their development into adult continues in their mothers pouch. The development of young devils is detailed in the table below.

 

 

Approximate Age: Significant Developmental Achievements:
3 weeks
  • Ears begin to form
  • Lips and whiskers begin to form and become noticeable
6 Weeks
  • Reach, approximately, the size of a walnut
8 weeks (2 months)
  • Pink colouration fades and skin begins to thicken
  • Pigmentation begins and starts from the tip of the nose, before working its way down the rest of the body
  • Individual markings start to arise
12 weeks (3 months)
  • Eyes begin opening
  • Squeaking noises start to be heard, while still attached to the teat
16 weeks (4 months)
  • Begin emerging from pouch
  •  Play with siblings begins
20 weeks (5 months)
  •  Weaning begins
  •  Sibling play becomes more aggressive
24 weeks (6 months)
  • Young become fully weaned
40 weeks (10 months)
  • Young start to demonstrate independent behaviours, e.g., exploring outside of the den without their mother
45 weeks (11 months)
  • Become separated from their mother
12 months
  • Become separated from their siblings
24 months
  • Considered adults and reproductive behaviours may be demonstrated

Lifespan  

On average, the lifespan of devils in the wild is between 5 and 6 years, while devils in captivity general survive to around 7 or 8 years.

Hair loss along the tail and the back of the devils body becomes evident as devils age. Facial scarring may also determine age, with older males often being in more confrontations than younger males. Devil teeth tend to wear more quickly than they grow and therefore older devils often demonstrate greater tooth wear than younger devils.