Tasmanian Devil (Sarcophilus harrisii) Fact Sheet: Reproduction & Development

• When a female is about to be in estrus, she loses her appetite, becomes aggressive, and retreats into hiding (Kelly 1993)
• Once female is in estrus, she is submissive towards male (Kelly 1993)
• Females "aggressively assert preference for older and larger males" (Jones 2008)
• A male determinedly and aggressively guards his mate from other males, often sequestering her in a den (Owen & Pemberton 2005)
• Most Devil Facial Tumor Disease (DFTD) is probably spread in breeding season when many aggressive injuries occur (Pearse & Swift 2006)

• Mating occurs in March during any time of the day or night (Guiler 1970)
• Estrus cycle lasts 35 days (Jones 2008)
• Immediately after mating, female once again becomes aggressive again towards male (Kelly 1993)
• Females are capable of false pregnancies (Guiler 1970)
• A female may replace a lost litter if she breeds again early enough in the season (Guiler 1970)

• No embryonic diapause (delayed implantation of embryo, depending on environmental & health factors) 
• Gestation period: 31 days (Guiler 1970)

Birth (Guiler 1970)

• Season of birth in wild: typically March-July (fall-winter of southern hemisphere), although some females give birth in July-September
• More young are born than can attach to a teat (Jones 2008)
• Litter size: 1-4, with a single young is the least common (Jones 2008)
• Newborn weight: 0.18-0.29 g (0.01 oz and less)
• Body is pink and hairless
• Newborns have well-developed digits with claws
• Facial vibrissae (sensitive long hairs) first appear around 17 days
• Devils are born with eyes present only as spots; young are blind until 3 months of age
  • Eye slits visible around 16 days
  • Eyelashes appear around 49 days
  • Eyes finally open around 90 days
• No external ears or ear openings are visible at birth
  • Ears (pinna) become erect and free of head around 76 days

Infant/pouch life (< 1 year old) (Guiler 1970)

• Young can not relax its hold on the teat until about 100 days
• Pouch life ends around 105 days; duration similar for other members of dasyurid family
  • An eastern gray kangaroo by contrast has a pouch life of 300 days
• Infant weaned at about 7 months (November in Tasmania)
  • Most other members of the dasyurid family wean at 3-4 months (Lee et al. 1982)
• Young become independent around 9 months
• After pouch life, young usually left in den while female hunts; occasionally ride on mother's back 

Subadult (1-2 yrs old)

•  See note below regarding earlier sexual maturity due to DFTD

Adult

• Females do not breed until second year (Guiler 1970)
  • Other dasyurids mature in approximately 11 months or less (Lee et al.1982)
• New studies indicate the severe population decline due to DFTD is changing the devil's life history patterns:
  • DFTD affects adults less than 2 years old; the disease is consistently fatal (Jones 2008)
  • Females now breed by 1 year
  • This may be the "first known case of infectious disease leading to increased early reproduction in a mammal" (Jones 2008)

Wild populations

• About 3–4 years, prior to the late 1990s outbreak of a contagious, fatal disease (Devil Facial Tumor Disease) (Rose et al. 2017)

Managed care

• No AZA estimates

• Devil Facial Tumor Disease (DFTD) has spread over 80% of the land area of Tasmania (Lanzenby et al. 2018)
• Has caused marked shift in age structure, with individuals 3 yr and older now rare in areas affected by DFTD (Lachish et al. 2007, McCallum et al. 2009)
• Populations compensating by now breeding younger, which results in younger individuals contracting the disease earlier in life (Jones et al. 2008; Lazenby et al. 2018)
• Small and potentially fragmented populations caused by DFTD susceptible to other threats, such as deaths from strikes by motor vehicles and disasters (e.g., wildfires, drought)
• DFTD first reported in 1996 (Hawkins et al. 2006)
• Mortality of infants in wild during pouch life very low; juveniles out of the pouch, however, suffer high rates of mortality (Guiler 1970)

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

Buchmann & Guiler (1977)
Fleay (1935)
Guiler (1970)
Hawkins et al. (2008)
Jones (2008)
Jones et al. (2008)
Kelly (1993)
Lee et al. (1982)
Owen & Pemberton (2005)
Pearse & Swift (2006)
Slater (1993)