Komodo Dragon (Varanus komodoensis) Fact Sheet: Physical Characteristics

Body measurements

Body size

• Largest living lizard
• Juveniles slender and agile
• Adults more robust, with flatter bodies and proportionately shorter tails (compared to juveniles)
• Males larger than females
• Long neck for viewing surroundings (e.g., in tall grass)
  • Can raise head up to 40 cm (1 ft) above the ground
  • When lowered, head approximately 20 cm (0.7 ft) above ground

Traits

• Toes have sharp, recurved claws
• Lightweight skull (Fry et al. 2015)
  • Weak bite force in proportion to body mass
    • Strong pulling force allows them to de-flesh with high success (D'Amore et al. 2011)
• Teeth specialized for catching and holding prey, as well as tearing/removing teeth
  • Serrated, laterally compressed , and curved backward
  • Sharp tip and broad base
  • Longest teeth are approximately 2 cm (0.8 in)
  • Use of a bite and slice strategy that creates a severe wound (Fry et al. 2015)
  • Komodo has 4-5 replacement teeth at each position
    • Many varanids have 1-2 replacement teeth
• Venom produced by toxin-secreting glands of monitor lizards (Fry et al. 2006; Fry et al. 2009)
  • Facilitates blood loss after bite by causing persistent bleeding, leading to hypotension, of prey (Dobson et al. 2019)
  • Toxin of the lace monitor (Varanus varius) affects blood pressure and clotting ability of its prey
• Short intestine
  • Carnivore diets (those high in proteins and lipids) don't require a great deal of digestive processing
• Skin
  • Covered by osteoderms
    • Often compared to chain mail
  • Shedding occurs in patches
    • Begins in September
    • Lasts about 6 months each year
• Tongue long and narrow, with a deep fork at its tip
  • Retracts into sheath inside the mouth; does not move freely
  • Partially supported by a complex structure of bone and cartilage called the hyoid apparatus
  • Used for locating prey and in social interactions
    • Not used to manipulate food, as in some other lizards

Coloration

• Most adults uniformly gray or clay-colored
  • Brighter, speckled skin until reach 4 years of age
    • Komodos of Flores retain brighter coloration
• Little sexual dimorphism
  • Flanks of adult females more red than males
  • Yellowish-green nose spots more common in males
• Light yellow tongue is species specific:
  • V. salvator has a blue tongue
  • V. dumerili and V. grayi have pink tongues

Olfaction

• Sense of smell important in food detection
  • Komodo dragons can detect the scent of carrion from as far as 11 km (6.8 mi)
  • Decomposition releases volatile oils that Komodo dragons can detect
• A pair of Jacobson's organs opens into the roof of the mouth
  • Scent particles collected by forked tongue and delivered to these sense organs
• Each external nostril leads to a multi-chambered nasal capsule
  • One of the chambers functions to excrete excess sodium 

Vision

• Keen eyesight
• Eyes placed laterally
• Covered by 2 different eyelids
  • Upper lid has little mobility
  • Lower lid contains a cartilaginous plate that slides over surface of the eye

Hearing

• Ear is important for maintaining balance, as well as sound reception
• Behavior more scent than sound oriented

Respiration

• Varanid lungs larger than those of most reptiles
• Take in relatively large amounts of oxygen and their physiology produces a more efficient system of air circulation
• Breathing rate is regular and low
• Varanids can voluntarily hold their breath for long periods

Circulation

• Varanids have a more complex heart structure and blood chemistry than other lizards
  • Allows them to achieve intense activity without becoming exhausted

Water/salt balance

• Water makes up 70% of a lizard's body weight (10% more than in humans)
• Varanid skin is covered with scales and contains no sweat glands
• Excess sodium removed by special salt-secreting glands in the nasal capsules

The chain mail-like scales covering a Komodo dragon's body protect its skin.

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

Auffenberg (1981)
Ciofi (2004)
D'Amore et al. (2011)
De Lisle (1996)
Dobson et al. (2019)
King & Green (1993)
Fry et al. (2006)
Fry et al. (2009)
Fry et al. (2015)