Eastern Blue-tongued Skink (Tiliqua scincoides) Fact Sheet: Physical Characteristics

Body measurements

Data sources: Cogger (2014), Wilson and Swan (2017), *Hoser (1989)

Body

• Large and long (Cogger 2014; Wilson and Swan 2017)
  • Skink body more bulky, compared to similarly sized lizards
  • T. s. intermedia larger than T. s. scincoides
• Scales smooth and glossy (Horner 2004; Cogger 2014)

Coloration and pattern

• Upper body pale silvery-gray to brown with longitudinal bands from neck to tip of tail (Cogger 2014)
  • Cryptic coloration in leaf litter and ground debris (Horner 2004)
    • Patterning breaks up body contours
      • Hard for other animals to see
• Paler scales usually have dark edges on the sides (Cogger 2014)
  • May appear as narrow, dark brown bands
• Darker bands may have some small white spots (Cogger 2014)
• Subspecies distinct (Cogger 2014; Cronin 2014; Wilson and Swan 2017, except as noted)
  • T. s. scincoides (southern/eastern Australia)
    • Color and pattern highly variable
    • 6-9 pale bands between nape of neck and hips; 7-10 on tail
    • Often a dark streak from eye to ear
  • T. s. intermedia (northern Australia)
    • Rich brown with irregular, less distinct bands
      • Bands pale, yellow, or cream-orange
        • Mottled and variegated
    • Dark streak behind eye may be faint or absent
    • Head pale brown
    • Head may have dark speckles and heavy marbling (Horner 2004)
• Underbody white, gray, or pale yellow (Cogger 2014)

Head and mouth

• Head
  • Wedge-shaped (Horner 2004)
  • Distinct from neck (Horner 2004)
  • Slightly flattened (Cronin 2014)
• Tongue blue (Abramjan et al. 2015, except as noted)
  • Protruded during defense display (Abbate et al. 2009)
    • Discourages predators and other potential aggressors (Horner 2004)
  • Conspicuous
    • Broad and flat (Wilson 2012)
      • Visually fills the oral cavity
    • Strong contrast between blue- and pink-colored mouth areas
      • Mouth tissues reflect UV light
    • Possible role in intraspecific communication
• Temporal scales (behind eye) enlarged and long (Wilson and Swan 2017)
  • Much larger than surrounding scales (Cogger 2014)
• Ear openings conspicuous (Cogger 2014)
• Nasal head scales separated (Cogger 2014)
• Teeth short and blunt (Horner 2004)

Limbs

• Short (Cogger 2014)
• Four limbs, each with five equal-length toes (Cogger 2014)
  • Present in all Tiliqua

Tail

• Shorter than body (Cogger 2014)
• Thick (Wilson and Swan 2017)
  • Round (in cross-section) (Cogger 2014)
• Tapers to a point (Cogger 2014)

Subtle differences in some populations

(Phillips et al. 2016)

• Body length slightly larger in females than males
• Head slightly wider in adult males than females

Similar appearance to other blue-tongued skinks

• Body pattern similar to Tiliqua multifasciata (centralian blue-tongued skink)
• For dichotomous key of Tiliqua species, see Cogger (2014), p. 686

Hearing

• Sensitive to high frequency, high amplitude noise (e.g., mining machinery) (Mancera et al. 2017)

Smell / chemoreception

• See Communication (in Behavior & Ecology)

Metabolism

• Conserve energy during dry season (Christian et al. 2003)
  • Maintain lower body temperature
  • Less active
    • Less energy spent foraging and digesting food
      • Fewer insect prey available than during wet season
    • Also see Burrowing (in Other Behaviors)

Regulation of body temperature

• Metabolic heat (Bartholomew et al. 1965)
  • Important role in body temperature regulation
  • Body heat produced faster than it is dissipated
• Skin
  • Blood vessels promote heat exchange (Drane and Webb 1980)
    • Also see Porter and Witmer (2015)
• Brain (Cabanac et al. 1967; Hammel et al. 1967)
  • Feedback from brain influences skink thermoregulation behavior (i.e., selection of cooler habitat, if high temperature)
  • Neurons are temperature-sensitive

Tiliqua scincoides is a large lizard species with smooth scales and five equal-length toes.

The individual pictured above has cream-orange bands and—as is typical of this subspecies (T. s. intermedia)—lacks a dark streak behind its eye.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved. (Note: This is a cropped image.)

Similar to other lizards, blue-tongued skinks have a network of blood vessels just under the surface of their scales that helps them regulate their body temperature.

(Scale surface shown in solid white.)

Image source: Drane CR, Webb GJW. Functional morphology of the dermal vascular system of the Australian lizard Tiliqua scincoides. Herpetologica 1980 Mar;36(1):60–66. Figure 2, Diagram of the cutaneous vascular system of T. scincoides. (Based on Maderson PFA. 1964. The skin of lizards and snakes. Brit. J. Herpetol. 3: 151-154.). Note: This is a cropped image.

Image credit: © Herpetologica, The Herptetologists' League/British Journal of Herpetology, British Herpetological Society. All rights reserved. Used with permission from Allen Press Publishing Services.