Komodo Dragon (Varanus komodoensis) Fact Sheet: Behavior & Ecology

Daily patterns

• Primarily diurnal
  • Range: 4:30-23:30
  • Usual wake between 6:00 and 6:30
  • Activity peaks: 9:30 and 15:30
• Sunbask for majority of morning hours and some of afternoon
  • Seek shade mainly in the afternoon
• Sleep about 12 hours every day
  • Shelter in burrows and natural cavities, and under overhanging vegetation

Example statistics

• Adults spend an average of 26 days searching for prey, 10-20 minutes eating, 3-6 days is spent in digestive pause.

Seasonal changes

• Activity levels lowest in early part of dry season
• Activity increases at end of dry season and throughout the rainy season
  • Probably related to weaker prey

Body size affects behavior

• Body size influences ability to retain and dissipate body heat (thermoregulatory behavior)
  • Larger dragons heat and cool more slowly than smaller dragons
  • Medium-sized dragons active foragers, while larger dragons sit and wait for prey (Harlow et al. 2010)

Home range

• Range consists of a foraging area and a scavenging area
  • Foraging area has a smaller core area that includes shelter/burrows and thermoregulatory/basking sites
    • 50% of activity occurs in core area
    • Foraging area is 5-28 times larger than core area
      • For hatchlings, core area may be a clump of trees
      • For an adult, core area is 4.2 km², on average
  • Scavenging area determined by location of dead animals
    • Can be extremely large in adults
    • About 16 scavenging individuals occupy 1 km²
  • Travel about 2 km/day
    • Adults may travel up to 10 km/day
• Factors influencing home range:
  • Topography
  • Prey density
  • Social status
  • Size
  • Sex of individual

Dispersal

• Capable of long distance movement but exhibit high spacial fidelity (Jessop et al. 2018)
  • Individuals rarely move beyond the valleys in which they were born
  • Excellent homing and navigational abilities

Visual communication

• Threat display
  • Tail lashing and/or quivering, gaping mouth, gular inflation, and arched back (accompanied by hissing)
    • Subdominant individual usually flees
• Appeasement display
  • Licking, ritual walking, closed mouth (no hissing)
• Flight/escape behavior
  • Lunging and biting, scratching, and defecation
    • Regurgitation may occur in younger animals
• No sexual displays
  • Aggregations may be essential to successful breeding
    • May also establish and reinforce hierarchies

Vocalizations

• Hissing is one of few vocalizations of Komodo dragons
  • Usually associated with defensive behavior
  • Used during feeding, during attacks, and frequently by females during mating

Olfactory signals

• Fecal pellets deposited on trails
  • Chemical cues investigated by other Komodo dragons (using their tongues)
• Scent plays an important role in territorial marking and while hunting
• Rubbing behavior
  • Smaller Komodos rub their bodies on the ground near or in carrion
    • Most rub themselves in hair or intestinal contents
  • Rubbing behavior not practiced by adults

Mainly solitary

• Interact at feeding sites and for breeding

Dominance hierarchies

• Based on sex and size, which determines position at feeding sites

Agonistic behavior

• Fighting between males often results in severe lacerations and even death

Territoriality

• Minimal to none
  • Foraging and scavenging areas very large and not easily defensible

Digging

• Excavate burrows; dig out bird (megapode) eggs; search for rodents, lizards and snakes
• Dig with front feet
  • One leg digs for several strokes, then the other
  • Hind legs not used to push out dirt
    • Backs up slowly, throwing the dirt with fore limbs

Body temperature regulation

• Ectothermic
  • Raise body temperature by sunbasking and absorbing energy from warm surfaces
  • Lower body temperature by seeking shade or burrowing
• "Gular fluttering" or "hyoid panting" is used only in cases of extreme overheating
  • Mouth held open and gular region of throat is inflated with air; air expelled in fluttering fashion
• Dig dens to protect themselves from overheating
  • May also occupy thickets or burrows at night to regulate their body temperature
• Body temperatures of individuals drop to as low as 20ºC (68ºF) at night and can reach above 40ºC (100ºF) during the day
• Drinking by immersing snout to the eyes, suck up water, then raise head and allow water to run down throat (similar to snakes)
  • Most manage without free water from April through December

Ethogram

• For behavioral inventory, see Auffenberg (1981), p. 124-127

Resource competition

• Feral dogs, humans, and medium-sized Komodos compete for same major resources (deer & boar) (Auffenberg 1981)

Space use

• Varanus salvator avoids contact with larger Komodo dragons (sympatric on only one island) (Auffenberg 1981)
• Smaller animals use Komodo dragon burrows for shelter (Auffenberg 1981)
  • Snakes, lizards, and rats

Walking and running

• Quadrupedal, plantigrade
• Body, head, and tail undulate from side-to-side
• While running, body and tail are held fairly rigid; hind feet move in wide lateral arc
  • Tail raised off the ground
• Speeds
  • Walking: 4.8 km/hr (3 mi/hr).
  • Running: 14-18.5 km/hr (8.7-11 mi/hr)
    • Short distances only

Swimming

• Most monitors are good swimmers. Diving and swimming under water is effective escape behavior.
• Limbs are folded against the side of the body, and the tail is used to propel the lizard while swimming (Shaw 2002)
• Longest known swim: between the islands of Komodo and Nusa Mbarapu, a distance of at least 450 m. (a bit over 1/4 mile)

Tree climbing

• Climb trees as hatchlings and juveniles
  • Lose ability at larger body size
• Only very young lizards jump from branch to branch

Komodo dragons use their sense of smell to detect territory boundaries of other dragons and track wounded prey.

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

Auffenberg (1978, 1981)
Bennett (1998)
Burden (1927)
Harlow et al. (2010)
Jessop et al. (2018) 
Lange (1989)
Lutz & Lutz (1991)
Imansyah et al. (2008)