Komodo Dragon (Varanus komodoensis) Fact Sheet: Reproduction & Development

Nest construction

• Females typically digs nests from June-August (Ariefiandy et al. 2015, Purwandana et al. 2016)
  • Excavated in soil or nests of mound-building birds (called megapodes)

Parental care

• Female guards nest August-December

Courtship

• Male courtship behavior
  • Rubs chin on female's back and neck
  • Hard scratches to female's back
  • Tongue-licks area around hind legs, shoulders, neck, and head

Copulation

• Mating occurs quickly
• Male restrain female to mat and avoid injury
  • Female bite and tail-slaps male, if too aggressive
• Mounting occurs several times in each courtship sequence

Sexual maturity

• Occurs at 5-7 years (both sexes)
  • Females: first reproduction at 7-10 years (data from populations in managed care)

Breeding season

• Courtship and mating have been observed from January-October (wild and managed care populations)
  • Successful mating from late June-October
• No breeding territories
  • Courtship and mating take place in small aggregations near feeding sites

Egg laying

• Most females lay only one egg clutch per year
  • July to early September
• Clutch size
  • 21 eggs, on average (range: 1-30) (Purwandana et al. 2020)
• Females may lay one or more eggs, several times during successive days
• Female breeding ability thought to decline around age of 20 and cease around 30 yrs
• Incubation period
  • 2.5 - 8 months (influences temperature and soil moisture).
    • About 220 days in managed care
• Egg description
  • Dimensions
    • Approximately 4 x 2.25 in
  • Soft, leathery shell (like all varanids)
• Weight at hatching
  • About 80 g (2.8 oz)
• Size at hatching
  • 4.9 cm (1.9 in), on average
• Timing of hatching
  • Young hatch February-May

Sex ratios

(Tim Jessop, personal communication, 2017)

• Sex ratios among age stages not well known for wild populations
  • From hatching until maturity, sex ratios appear to be approximately 1:1
  • Genetic testing used to diagnose sex
    • Morphological approaches (e.g., Auffenburg 1981) are less accurate
      • See Halverson and Spelman (2002)
• Breeding females experience reproductive costs (Tim Jessop, personal communication, 2017)
  • Reduced life expectancy, leading to a male-biased sex ratio among adult Komodo dragons
    • Also see Laver et al. (2012)

Asexual reproduction

• Parthenogenesis observed in managed care (Sunter 2008)
  • Embryo develops from unfertilized egg when male is not present
  • Offspring always male
  • Impacts managed care breeding populations
    • Reduced genetic diversity
    • Fewer females available for breeding

• Young are arboreal their first year (Ariefiandy et al. 2015; Purwandana et al. 2016)
  • Also see Habitat
• Siblings may remain together in small groups for several months after hatching

Wild populations

• Males
  • Most do not live past 30 to 40 years (Tim Jessop, personal communication, 2023)
• Females
  • Most do not live past 20 years (Tim Jessop, personal communication, 2023)

Managed care

• Median life expectancy (AZA 2023)
  • Males: 19.5 years
  • Females: 12.9 years

In their first year, Komodo dragons live in trees to avoid predators.

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

Auffenberg (1981)
IUCN/SSC CBSG (1994)
Judd & Bacon (1977)
Purwandana et al. (2016)